IMHO, You won't be happy with one of those Van Class B's the bathrooms are a killer and all in all they ARE inside just the size of a van!
Check out the Sprinters. I looked at Thor's Four Winds version and wow is it nice. Roomy, tall, great floor plans that you can actually walk around in, easy in and out and drives like a car.
I'm thinking of down sizing from my 31 foot to one of these. Almost all of my sporting event Rv';ers have switched to them. Both DH and DW's love em. and the gas mileage is outstanding. I looked at them all and found that IMHO Four Winds was the nicest.
http://fourwinds-classc.com/