Just what you wanted, another opinion, but here goes.
From your description of what you have, I would pick the low hanging fruit first.
I am sure you KNOW roughly of your collection, what is desirable and will bring some money. The engines. Period. And not all of them, just certain ones.
So, that said, to maximize your return I would:
Take pictures of everything. Do group shots if too many or just don't feel like sorting stuff. Can always take individual pic's if people want them.
List the PA engines and throw in the accessories, listed here in the classifieds. Make a list, decide your lowest acceptable price, then list it, and expect to get offered even lower.
Carbon props, pipes, headers, etc. - If they aren't dinged up, list them here, they still bring good money, and some are hard to find.
List the sparkers that people want the most, (Like the Anderson Spit, Madewell's, Doolings, whatever, because they still use them in OTS and other events) on here in classifieds, and again, follow the pricing motto above.
List the rest of the engines as a lot or lot's by type on Ebay, because you don't sound like you want to mess with a lot of individual sales. Take lots of pictures. Itemize the list in text format for the add, take a group shot, and ignore people who just want to cherry pick one engine. Set your reserve price, and as long as they hit your reserve, be willing to wave bye bye to all of them for that, anything else is gravy.
Kits - Pull the current modern designs you know people want to build and fly. Kit manufacturers are drying up, and some people will want them. List them here, priced for here as above.
Kits - Collectable kits, put on ebay. Buyer to pay actual shipping, set a reserve, but make it reasonable or you'll be re-listing them.
The rest - Offer to local clubs at swap meet, or put a curb-alert on Craigs list if your local clubs don't want it (because if those cheapskates don't want it, nobody does, LOL!)
That's as honest of a Dutch uncle type advice as I can give. We can't take this crap with us, that's for sure, and you don't want to stick your family with the job, they'll just cherry pick something to remember you by and chuck the rest.
Hope that helps,
Eric