I'd also pick up:
- something to tie down the awning. I use a couple of ratcheting tie downs with a bright colored straps so you can see them better at night and a screw type peg.
- RV-specific toilet paper
- water heater rinsing wand
For the trailer coupler I use something like this to lock the coupler and to hold up the electrical connection cable and the breakaway switch wire.
http://www.etrailer.com/Hitch-Access...sky/80235.html
I'm like the others here who use 2x12s for under the low side wheels. I have one long enough to sit the 2 wheels on and a 2nd, 2 to 3 feet longer, to go under the first and ramp the wheels up onto the shorter one if I need the extra height.
I also have a couple stacks of cut up 2x12s screwed together for use under the stabilizers. I need them anyway to level the Roo in my driveway so they come camping with us just in case they're needed. I also have one bag of Lynx Levelers. I haven't needed more than that so far.