Just do what you can do. I guess you will need to rent a storage unit for the stuff that won't fit , the stuff that does just shove it in what ever place you wont trip over it and then unpack at a pace that isn't going to make you stark raving crazy.

I can relate , my husband keeps everything. I am the complete opposite I throw out stuff , I can not do clutter .

Good luck , "try" and be kind to yourself as much as possible.