Along the lines of packing, something that helps me for RV trips or airplane trips or just about any trip out of the house that I need to bring things: Have a sacred spot in you house where you put things that need to go with you. I also keep a list in this spot.
For me, it's my work bench in the garage. A couple days before a trip I start a little list and start to pile things up on the bench. When I leave the house if it's on the bench it goes with me, if it's on the list and not on the bench I go get it. If I haven't thought of it in several days? I guess it's hopeless and wasn't meant to be :)
For me, it's all about having a single point that everything passes through. Small things go on the bench. Luggage and larger things go on the floor in front of it. As I'm leaving the garage for the last time I just look at the bench and on the floor nearby. Honestly, I can't remember the last time I left anything of any significance at home so I'm sticking with my routine.