You can claim the interest paid on the RV. A camper or Recreational Vehicle (RV) meets the IRS definition of a second home if it contains sleeping, bathroom and kitchen facilities. Interest paid on a loan for the purchase of a recreational vehicle is therefore tax deductible as valid home interest on a second home ( As per IRS publication 936-http://www.irs.gov/pub/irs-pdf/p936.pdf).
Once you are in your tax return, click on the “Federal Taxes” tab ("Personal" tab in TurboTax Home & Business)
Next click on “Deductions and credits”
Next click on "jump to full list" or “I’ll choose what I work on”
Scroll down the screen until to come to the section “Your Home”
Choose "show more", then Mortgage Interest and Refinancing and follow the onscreen instructions.
Or, log into your online account, begin working on your tax return, and then type the text string "mortgage interest" into the Find / Search box near the top. When the "Jump To" link appears beneath, click it and the program should take you where you need to go in the software.