I'm going with the "king tut" plan.
Seriously, I'm grading a few of the nicer things just in case. And my wife is fairly knowledgeable. She also knows who to call if she can't deal with it all. (Multiple people across many hobbies)
I'm hoping my daughter will take an interest in some portion of the collections and build on them. She's not quite 2, so I'll have to wait a while and see. I do know that she found her first card to be very tasty, and has a great time with the empty toploader I gave her when she was being too grabby while I was sorting some cards.
The massive assortment of modern extras is all going away fairly soon. Sent some of it to a localish auction and did fairly well.
Some of the better collections I'm putting together some info on, a website for one, and an album for another with all the important info.
Someday if I find the right place the bikes may go to a museum. That collection is good enough, but sending some of them off would hurt a bit.
Nick Basbanes wrote a book about book collectors that had a wonderful chapter about how differnt collectors handled this very thing. The methods ran the entire spectrum. Donation to a university, sale after passing, special auction while still around etc. The guy who auctioned his stuff enjoyed seeing a new generation get excited about the stuff he'd gathered and been excited about.
Steve B