Tax question

First, a singular RV can be a home in tax terms so because of that it could be a rental on Schedule E, if you are renting it out as a guest house of sorts. 

However if it is mobile and it is being rented and your renters take the RV to a vacation spot or campground  as example, it would be considered personal property and not real property for tax purposes. Either way you can choose section 179 which allows the full cost deduction in the year placed in service.

Schedule E: It could be depreciated over 10 years in the first scenario.

Schedule C: It would be depreciated over 5 years in the second scenario.

Dwelling unit.  

A dwelling unit includes a house, apartment, condominium, mobile home, boat, vacation home, or similar property. It also includes all structures or other property belonging to the dwelling unit. A dwelling unit has basic living accommodations, such as sleeping space, a toilet, and cooking facilities. 

A dwelling unit doesn’t include property (or part of the property) used solely as a hotel, motel, inn, or similar establishment. Property is used solely as a hotel, motel, inn, or similar establishment if it is regularly available for occupancy by paying customers and isn’t used by an owner as a home during the year.