I’ve spent a fair amount of time in Florida, although not a full year, mainly only summers. Traditional air conditioners require either shore power or a generator, they’re not going to work with solar. Swamp coolers, especially the indirect type, and ice coolers work, and need very little power and run on 12v. My indirect swamp cooler works perfectly, and it only draws 1-3 amps.
Only low top vans will fit in parking garages, and not even all of them. You need to know the height of the garage, and then measure the height of the van. You probably won’t be able to add solar panels, but no great loss there anyway. I mainly charge my house battery while driving via an isolator and 99% of the time that’s all I need. I only need to fire up my generator if I’m boondocking for prolonged periods.
Any of the big 3 makes of vans are probably acceptable, I like Dodge’s myself, because overall they seem to be the most reliable, at least the older ones. I try to stick to the pre 90’s vans, because about that time, all of them started having major engine or transmission problems, not to mention electrical problems. I think that’s when quality was overthrown by greed in the American auto industry.
I like full sized window vans, but you might want to consider mini vans as well. If you’re mainly a city dweller, some handicap vans have a lowered floor, and while not good off road, they can give you interior height without adding height to vehicle itself. I had a Dodge Caravan with a lowered floor that I could almost stand up in. A chair or stool on wheels can make navigating the interior of a low top van easy. I have a swivel, reclining, desk chair that I use. Combined with a folding tripod stool, it is as comfortable as any recliner. A TV tray provides an instant desk or dining room table, that can be used outside as well.
Builds don’t need to be expensive or complicated. I basically just move my camper interior in and secure it, rather than actually building anything in. Just remove the rear seats and move your new interior in. I keep everything below the window line except for my toilet/shower curtain, which I only raise when I’m using them. This gives me a great view, and a more open and less cramped feeling.
Good luck & keep us posted.