CandleMom -- first, welcome to our group!!!
Now... I don't have any suggestions, unfortunately. I mean, I know what to do... it is just sooo hard to do. DH, DS, and I are ALL terrible packrats... terribly sentimental... also hate to be wasteful ("I might need that sometime.") You can look at today's PWYC and see how far I've progressed in my "guest" room, which certainly is not ready for any guests!!!
I think what we are SUPPOSED to do is get in there and throw out a ton of stuff, b/c we KNOW we will still have the memory, even if we don't have the electric football game... and no it is not going to be worth whatever $ we would make on e-bay or in a yard sale to try to sell it... and ds didn't even play with it much when he was little anyway, so what kind of memory are we trying to preserve? Are we going to FORGET that yes, ds was indeed a child once upon a time???
See, I can talk the talk... I just can't walk the walk.
Now, once you get in the proper mindset to throw out stuff, I think the rest falls in place pretty well. Get a bag or box for throw away, a bag or box for keep, and start at the door and work your way around the room.
Some would say work 15 minutes at a time, but I don't even get started good in 15 minutes. 30 minutes would work better for me.
Sort & trash for 30 minutes, then carry the trash bag to the trash, and put all the stuff in the keep bag where it goes.
Like you said, there's the rub. That's the problem I'm facing now... Where DOES it go???
Maybe someone else will post and and give us both some better advice! I just posted so you'd know you're not alone!