It would seem to me that if you use the RV for OCCASSIONAL business travel, it would legitmate to claim related MILEAGE and and OTHER BUSINESS EXPENSES RELATED TO THAT TRIP.
Unfortunately, you will have to use IRS mileage allowance rather than the $0.50-$0.60 per mile that it actually costs, but you can probably claim related camping fees, which are probably less than motel/hotel costs if you took you car on a business trip.
Meals???? What is the IRS per diem allowance?
Interest, you can claim that anyway as a second home, or as a business expense if you purchased the rig for your business as a capital item.
Depreciation, NO, unless the rig was spec-ifically purchased for the business as a capital item.
I would treat it the same way as if you had used your car and stayed in a motel...
I would also confer with a professional tax accountant/CPA.