I wouldn't want anything bigger than a B for a daily use vehicle.
How do you plan on using an RV? If it just for weekend camping or touring maybe something even smaller would work. Like the http://www.gtrv.com/models
If you need more space then a full Class B would work. If is is not a diesel then expect 15 mpg + or -. I think for daily use shorter is better for maneuvering. Probably even more important is the width. I had a 21' B+ that had a rear full bathroom and full kitchen. http://www.classbforum.com/phpBB2/vi...php?f=33&t=537
I was a full 8' wide though. It would really fill a parking spot. Too wide for a daily drive I think.
Islander (also out of business) made something you'd probably like:
I just love that one.