Urgh, don't tell me about books. I'm such a collector, and have hundreds of books. They reside in totes, wardrobes, tote bags and the bookshelves. And I still have hundreds on my kindle that I don't have physical copies of. It's an obsession. I was going to donate some, but they only take pristine condition books here now, there are so many in thrift stores. I used to be heartbroken by the great books we threw away when I volunteered. I try to move them on to good homes, but it is seriously hard to offload books here, but I can't just throw them away! I might take some to my MIL's place when we go next weekend, they might make it into the thrift stores in a smaller town, I often find good older stuff when I shop there.
If your books are already in the place of your risers, I agree with the digitizing option, keeping the artwork if possible. Do you have a scanner if the plastic cases are not the kind with inserts? I'm sure you could find a pony person willing to scan them in for you nearby, or I guess you could ship them, or there's probably a copy shop locally that can give you a USB copy. I must say though that most of the original episodes are available on DVD, with the exception of the specials (if you have them, upload them somewhere online for safekeeping when you digitize them, they'll be hard to find again and DVD's do wear or get damaged if that's the route you go) and they are much better quality, obviously. I started burning mine to DVD for my niece before the DVD's came out here, and the result wasn't great, but then the original material wasn't really either.