For building and understanding gears, etc., I think the "building robots with lego mindstorms nxt" is good (it's what we've been looking through, although haven't cracked into it deeply yet). It definitely emphasizes the building over the programming, so that might be another angle to look at unless your ds is very comfortable already with that part. Good idea on alternate storage, I never think about stuff like that but it would certainly help things go faster to sort most parts ahead of time.
Hope he enjoys it!
