It doesn’t matter what you do with the proceeds when you sell your home. The law changed years ago. Now you can avoid taxes on up to $250,000 in capital gains taxes on the sale of your personal residence (or $500,000 if filing a joint return). Enjoy life in your RV. And if you have a gain on it when you eventually sell it, it will depend if it was permanently located as to whether you can deduct any gains.
I’m suspecting that you will have money “left over” after you purchase the RV. Put it in the bank, safely, in CDs or a money market deposit account. You won’t get rich, but you won’t lose a penny!