Am I completely crazy?

I would look at the representative sample of the RV parks you want to stay at and look at the nightly rate. Some may have a weekly rate you can take advantage of. Then determine how far you will go each week and calculate the fuel costs. Put aside money for maintenance. Then look at how much you are currently paying for food, clothing, etc. Look at your data plan on your phone and see if you have enough if you are on the road. You also did not state if you have the money to purchase the RV without getting a loan.

After you have done that, you can decide if you can afford it. If you can, then I would definitely go for it. This could be a wonderful adventure for you and your family.