If your RV qualifies as your second home, enter the interest as mortgage interest. You'll enter the property tax for the RV as personal property tax. These expenses are only deductible if you use itemized deductions (Schedule A) instead of the standard deduction.
The Tax Cuts and Jobs Act of 2017 nearly doubled the
standard deduction amount for tax years 2018 through 2025.
In addition, the SALT deduction (state, local, property, and
sales tax) is now capped at $10,000 ($5,000 for couples filing separately),
whereas in prior tax years there was no cap.
As a result of these and other tax law changes, our estimate
is that nearly 90% of tax filers will now be taking the higher standard
deduction, up from around 70% last year. And if you're in the 90% group, you
won't see a change in your refund after entering your mortgage interest and
property taxes.