Big box store bikes always need adjustments by a person with bike repair experience in order to work properly and have any chance of longevity. Actually, bike shop bikes do also, but the shop mechanics do that before you get the bike. Same with most used bikes, unless you know how to evaluate bike condition.
It's certainly possible to get lucky with one of these two "cheaper" options, but going with a real bike shop will be a sure thing. Besides all the initial adjustments, most even offer a free tune up at 6 months or so.
Especially since you want to ride long distances, (and want a bike that will be up for it) I'd suggest you stick with a real bike shop.