Not mentioned so far: WiFi range extender, if you're traveling with grandchildren look into a washer/dryer, breaker bar with socket for emergency removal of tire, tools suitable for tightening things and quick repairs, consider a portable waste water tank.
For us, the very first thing out the door was the lousy Denver mattress. We put in a 12" bed in a box, which helped a lot.
I recommend that you provision your kitchen with new pots/pans/towels, flatware, cooking utensils and the like. I keep crystal stemware and bar glasses...a conceit, but I do not like to drink out of Styrofoam (it's hard on the flavor of good scotch, or bad scotch for that matter).