I agree with all the posts above. I carry a bit more because I started out in an older TT and found that water leaks can ruin a weekend real quick!!
I carry a few small pieces of pex water lines and the slip style fittings a couple 90 degree and straight also the ones with the nut on the end for the faucets so I don't need to carry a criping tool.
Fuses
tool kit from sears or harbor frieght.
Channel Locks
Small,medium,and large Axe. It is a pain to get a fire started if you can't make kindling or cant find any.
Extra clips for hitch pin.(I take mine off when we get to the campground so I don't walk into it)
Cooking grate for fire so you can cook your burgers and such.
Spare tire 4way lug wrench. Jack as stated above all the things the other folks listed.
Good luck and Happy camping!!!