I see. Its prob best to sell/trade for what you need or just store it. Since when you need x,y z piece of gear it will be halfway across the country & cost more in shipping then to acquire a replacement on craigslist, a flea market, goodwill etc. Most times even if it fits in Flat rate box, you will "need" the item asap& not want to wait. Shipping/storing seasonal items can be smart (depending on the condition of the items) I have sent bulky clothing items to the dry cleaners. Most dry cleaners offer free storage if you pay for the cleaning in advance, this way your gear is safe & clean for winter time.
Getting back to those inflatable sleep pads, My friend has 1 that cost him $125 He is Fucking stupid!!!!! That is an insane amount for a sleeping pad. I can see paying that much for a quality pair of boots that will be used daily & will last decades.
Framed packs are great if you are doing the at/pct but for stealth & to ensure you don't pack too much shit, stick with no frame (internal/external). Its much easier to stuff that sucker where it don't want to go. If you get some expensive ass yuppie pack for free don't turn it down because you have a Chinese made Vietnam era ALICE. Packs are a dime a dozen too & wear out, try a few to see what you prefer.