Great thread, everything so far has been mentioned. I believe tooth brush, vacuum, magic sponge (in fact I just wiped down the interior as there was lots of little marks from the previous owner. About 90% better!
I like Mequires vinyl care, it brings back the plastic to when it was new, provides UV protection and it smells good too.
I do need to work on the outside as there are bugs that have to go and a few spots that need to be touched up.
One of the nice things I carry to keep the crap on the outside is a cheap Costco 3x5 that I can take out and shake when it gets pine needles and what not. As well put it in the washer when it needs it. And worse case just buy a new one for about 15. Another is a real cool mat that I lay out next to the van. It drys quickly, folds fairly small and allows the water to drain through it. So even if slightly wet it still doesn't weigh much. This would go into the trailer with the camp chairs and wood.