I read one time that you should have the first campsite less than 20 miles from home so in case you do forget something, its not a far drive home to get it. Or the weekend before you leave, move into the RV and live in it.
I will guarantee you will have more than you ever need. I still have stuff that I bought when I first got the RV, IN A BOX, never opened. My husband took one of every tool that you would ever need to replace and engine and transmission and the second anything goes wrong, he calls for a tow and takes it to the mechanic. I am the same way, I had to have a BBQ and a screened room and still in the box.
If you don't use it at home, you won't need it on the road.