If you are over 300 lbs I would get an old fixed fork mountain bike with cromoly frame (in fact I am and I did). They are cheaper and better quality than any vintage road bikes, which are all either garbage or super expensive for their age. Should be able to get something under 100 bucks with 26 inch wheels that doesn't need much/any work.
Likewise new bikes are all pretty garbage unless you get into the 1000 dollar range. That workman will have to have most its components replaced with something better and the frame itself will be rusty in a year from every review I see. If you really want a cruiser get an 80 or 90s schwinn steel cruiser. They are quite nice bikes and very sturdy, sometimes people want 500 bucks or more for them but I see them for 100-200 sometimes. Just don't get a 2000s era walmart schwinn they are terrible now.
You might be OK on wheels but if you start losing spokes then go to this upgraded wheel. It is the upgraded version of the crappy alloy rim that all the low end bikes come with these days.
https://www.amazon.com/Wheel-Master-26-MTB-Rear/dp/B00AUHTIK6/ref=sr_1_39?ie=UTF8&qid=1526070458&sr=8-39&keywords=26+inch+wheels