You probably would be a LOT more comfortable in a small class C.  Or even a slightly larger classC or small class A.  
They have much larger fuel, water and grey tanks.  All of this is a requirement when you try dry camping for a long time.  
I had always wanted to travel in a fifth wheel while full timing in retirement, but the more that I think about it, and the large trailer to try to park it, I am glad that I have a 30' long Bounder and a gas engine.  Something about $45 oil changes are nice every 6 months.  Fuel filter every 8 - 10 years.  So much less expensive maintenance than the diesel engines take.
I am really happy that I do not need to back in a large trailer.  I can park my motorhome in really small campsites, where they might be to skinny to back a fifth wheel into it. 
And while traveling from one place to another, I can park at night near a city park, or church, and put down the jacks.  Go to bed.  I do not disturb anyone, and can leave quietly in the morning.
Good luck with your decision!
Fred.