The world's best cruisers for riding at the beach like what you want, would be SCHWINN bicycles that were made in Chicago Illinois during the 1960's and 1970's.
There are no others that come close to equalling the sixties and seventies era SCHWINNS. The fifties and forties era Schwinns are almost as good.
Virtually any American manufactured basic cruiser style bicycle, manufactured between the years 1935 and 1975, regardless of what manufacturer, would also be a very durable, reliable bicycle, even much more so than any Electra Townie, Jamis Earth Cruiser, or any modern cruiser!!!!
Simplicity has definite advantages when it comes to a simple Beach bike!!!
The ONE PIECE CRANK is the ultimate in practical simplicity on a beach cruiser bike where WEiGHT DOES NOT MATTER and the terrain is billiard table flat.
Comfort and stability are exactly what you want.
I will argue that the ancient American made "BALLOON TIRE" bicycles from the mid 1930's until the early 1960's would make the BEST BEACH CRUISER BICYCLES ON THE PLANET with very little work.
Why are the Schwinn bicycles of the sixties and seventies better than the "BALLOON TIRE" era bicycles from Schwinn and other American manufacturers?
The Reasons are very minor but they do come into play for a bicycle that will be left outside at one's beach house:
---Schwinn chrome plating was the finest in the world, and that zenith for that would be the period after 1955 through the seventies.
---Schwinn paintwork was the best quality in the industry. The enamel paint quality from about 1962 Schwinns onward is significantly more durable than anything from the fifties, forties, or thirties.
---Schwinn handlebar shapes were more refined and better from 1967 onward.
---Schwinn frame designs and their dimensions were better refined post 1959 for most and 1966 and later, for step through womens' frames. The 1966 and later SCHWINN frames (until the Chicago end, so 1966-1982), regardless of frame style, are the strongest most durable bicycle frames that any manufacturer has ever built! Those SCHWINN frames are also among the best riding, most comfortable, and most stable riding bicycle frames in the world, then or now. It is exactly what you would want in a beach cruiser.
---Schwinn pedals and seats and handlebar grips were the best after about 1965. The DELUXE MATTRESS SEAT (all black) fitted to late sixties tourist 10 speeds and fitted to all 1970-1979 Suburbans is one of the most durable comfortable seats ever made. Yes, that Deluxe Mattress seat weighs about 4 to 5 pounds but it is nicely shaped and it is comfortable and durable. Those old two tone colored S seats are horribly rock hard and not very confortable although most just like the neato two tone look with the S. Most factory seats prior to the mid sixties, were horrible like that, certainly anything from anyone before 1960..
The black rubberized covered mesinger T-85 spring saddle that is factory issue on the 1971 and later Collegiates is fantastic, as it is supremely comfortable, the most comfortable spring saddle in my opinion, and it is virtually indestructible, unless one lets it rust (the seats' springs).
The SCHWINN COMFORT GRIPS (black) that are factory issue on 1971 and later SUBURBAN models is in my opinion the most comfortable traditional handlebar grip ever produced.
.....Hey, certainly you can update and customize any ancient American made, Ashtabula 1 piece crank, traditional cruiser bicycle with say Schwinn 7881 handlebars, and Schwinn comfort grips, and those German made Schwinn Approved bow pedals that were fitted to every 1970-1977 Schwinn Suburban and similar bow pedals except without reflectors were fitted to several mid sixties on Schwinns.
Heck, you can swap out whatever 1/2 thread pedals on any ancient American made cruiser bike.
Same thing for the handlebars.......They are all going to be 25.4 handlebar clamp area, and 7/8" (22.2mm) outer tube diameter of the chromed steel handlebars.
All the old American manufactured bicycles featured 22.2mm stem diameter sizing, however SCHWINN changed in 1966 to 21.1mm stem diameter sizing SINCE THEY(schwinn) INTRODUCED THE STRONGEST, THICKER WALLED TUBE PORTION PART OF FORK WHERE IT RESIDES IN HEADTUBE, thus necessitating the change to the 21.1mm stem diameter. -----YOU CANNOT DIRECTLY INTERCHANGE 1965 Schwinn stem of 22.2mm WITH THE 1966 & later Schwinn stem of 21.1mm.--------- YOU MUST MATCH THE SIZING REQUIRED FOR WHATEVER YEAR MODEL FORK------- You have to remember that with old Schwinns of 1966 and later, or 1965 and earlier. The other American manufacturers stayed with the old longtime industry standard 22.2mm stem diameter after Schwinn went to 21.1mm in 1966. I am not certain however if and when perhaps some or perhaps one other US mfr did maybe go to 21.1mm, IF THEY EVER DID after the bike boom, post '75, or post '79 etc.. I do not know that. I do know that Panasonic (Japanese mfr) did use the post 1966 Schwinn standard 21.1mm stem sizing on many bikes in the mid to late seventies during the time when they were manufacturing certain bicycle models for Schwinn.
Basically though, heck, you can customize and gear the single speed beach cruiser however the hell that you like, for almost very little cost.
There are several major firms in the Greater Los Angeles California, Long Beach California area , Downy California......both are industrial working class , some might say less picturesque areas within 30 miles of the heart of LA, .....these major firms sell everything on the web related to building/customizing a simple beach cruiser.
Now, if you go after those 1938 through 1956 cruiser bicycles with the ridiculous do nothing springer forks, the "tanks" that are decorative that look like an antique motorcycle's gas tank, with fancy three color paint schemes and balloon wide whitewall tires, and every accessory imaginable, then you are going to need to speed at least ten Benjamin Franklins to get you one in an average condition. You see, there is a truly "nut-job" segment of such afficianados that covet and collect these most decked out, fancy, factory sold, accessorized, high line models (see the C.A.B.E. as there is a large subset of such "nut-jobs" within the cabe community). In reality, they are mechanically identical to ordinary basic models (THE BIKES WERE ALL SIMPLE, JUST DECKED OUT WITH EVERY DOO-DAD IMAGINABLE SO THEY (the bike mfrs) COULD SELL THEM FOR A LOT MORE TO PARENTS THAT WANTED LITTLE JIMMY TO HAVE THE PRESTIGE OF HAVING THE FANCIEST, MOST PREMIUM CADILLAC LIKE MODEL IN THE ENTIRE NEIGHBORHOOD. YEAH, THE PERCEPTION THAT JIMMY's PARENTS(jimmy's dad) WANTED TO PORTRAY TO OTHER PARENTS AND KIDS IS THAT, HE IS THE BEST DAD, AND A GREAT GUY WHO IS DOING REALLY WELL. Certainly, there was perhaps peer pressure from Little Jimmy and his neighborhood gang of pals and school friends to get the "cool" bike that was the really in bike that everyone at that age and era was just dying to get.
Hey though, if you aren't one of those crazy nut-jobs within the cabe that wants original 1943 US ROYAL tires on their factory fully decked out 1943 ____ bicycle, no matter if the tires are so cracked that they aren't safe to ride......etc
...................Hey most of the ancient cruisers were purchased by normal folks that knew the value of a dollar spent. Yes, didn't Opie Taylor's good friend, Johnny Paul, have the fanciest, neatest, most swell bicycle that a boy like Opie could ever want at that point in time.................... ...however Sheriff Andy Taylor was a local goverment employee, and being on a civil servant's salary, Sheriff Taylor knew the value of a dollar and the importance of not spending more than what you can afford to.
....... A Beach Cruiser does not require any technology or anything special in or on said bicycle!
In addition to doing a great job, I doubt that you'd find anything considered more "COOL" by most beach residents and beach visiting vacationers than a vintage-ancient American made one piece crank equipped cruiser in good condition!!!
As Captain Kangaroo often said on his morning tv show, "SCHWINN bikes are best." **
( ** certainly the good Captain was compensated for saying that, but he was indeed correct... )
The Schwinn family's operation in Chicago Illinois, USA did in fact build the best beach cruiser bicycles that the world has ever known.
You will not find any bicycle, past or present, at any price, that does a better job as a beach cruiser, than an ancient Chicago built SCHWINN!!!