Sorry, but this. I would expect a rate in the low teens, if you even get approved. I'm assuming you're looking at a long term loan for the RV, as that's the only way it'd be remotely affordable. On a 15 year loan, at 12%, you're looking at a ~$450/mo payment. That would likely push you over 50% DTI. Not to mention you'd pay $40k in interest over the course of the loan.

My suggestion is to resist the impulse to buy, and wait until you're in a better financial position to purchase such a high dollar discretionary item. Sucks to hear, but financially is the best choice.