I'm personally waiting to see about the ProMaster vans, but if I were to look for a used rig that can be used as a runabout, I'd look at the Pleasure Way Ascent or a Roadtrek SS Agile. They are 20 feet or so in length, and are a decent compromise between the Roadtrek 170 Versatile and the 22-24 feet extended Sprinters.
If you want to park in parking garages, you will have to get a Sportsmobile pop-top conversion. They only sell pop-tops with the short Sprinter, Ford, and Chevy chassis models. Even then, watch the clearance, as some 4x4s may make it too tall. Any other "B" going into a parking garage will get scalped in short order.