Imouthere56, I just happened to re-read your OP and concur from it that you already have the MH, so bearing that in mind, you'd still have your SnB costs and other general costs you already have although on a plus your utility bills for 6 months at the SnB would be less whilst you are not in residence, so the only additional expenses you would incur whilst travelling for those 6 months which are totally controllable by yourself are:
Fuel for the RV = totally controllable by yourself on how far you chose to travel
(you'd be using fuel at the SnB for the towed so awash on that if similar mileage)
CG Costs = again minimal if you boondock 95% of the time just entering odd nights to empty & refill
Just sayin' FWIW.