(Speaking from having a solar panel array and a wind turbine on our bus for the past 20 months, living in it fulltime in the SW USA).
IMO, in wind vs. solar, solar will serve you better in all but the most windy conditions. In most locations, sunshine is more predictable and stable. Even when it is windy, having a turbine on a bus brings turbulence due to the low mounting position, so the output is not steady, and it's hard on the turbine. And it's kinda noisy, especially at night when trying to sleep.
There is a US gov't website that has wind maps for every state, so go there before spending $ on a turbine setup. Our Air-X turbine needs steady winds of at least 8 MPH to get going and at that speed, makes only a tiny bit of juice.
I guess my feeling on it is to think heavily & do lots of research before relying solely on a wind turbine for electricity (in addition to your engine/alternator). The first real step in that area is to estimate your electrical needs for a day. There are worksheets available all over the www. From there you can estimate battery needs, and from there, a recharging strategy.
Switching gears to bus size...
During our travels, we try to avoid any large cities, but when we do need to navigate a parking lot for a retaurant, grocery store, or gas visit, the driver just needs to be patient and plan ahead a little. We usually park far away from the entrance of the store/restaurant, because most cars are parked up close so people can avoid the walk.
For fuel, I look for stations with high (or no) canopies that can accomodate big RVs. Our bus is 30' bumper to bumper, flat-front, front engine.
Good luck, keep us posted on what you decide to do. A fun future is in store with either a westy or a bus.