Walls and guttering
hi miss, it's obvious the previous owner did you no favors, in the placement of the shed. nor your neighbors sympathetic to your situation to finish it in the manner you'd like. it's not worth getting into a pi$$ing contest/feud, with neighbor! that may be why it wasn't finished before? by two sides, I assume you mean near their outbuilding and the trampoline? that being said, if you want to finish your shed there? it can be done, though not in traditional way. first, you'll need some help. I've had to build 27 floor of fireproof 1" core board gypsum shafts around an operating elevator, and or around functioning industrial machines all without shutting machines or elevators down! you just have to figure out how to work from inside your box. you simply need to use tools usable in tight spaces. a 90 degree angled drill ( shallow profile) will allow you to fasten your outside material with as little as 6" of space. if you want some type of lap siding? you just start from the bottom as usual, and work from the inside, reaching out through between studs. it's time consuming, but doable. if you want some type of 4x8 sheeting? it's doable with help, just measure your studs and pre start screws, pre glued studs, and pass everything down from the top up through rafters and down along wall. one can reach 16-24" from either side to sink screws the studs at 32" if needed? glue good and use blind clips, like we use for pre papered drywall. fasten clips to inside of sheathing, slip into place on stud clips, pull sheething in tight and let glue dry. you can install soffits from inside, fascia and gutters from the roof just leaning out between rafters. you may have to finish roofing sheething and shingles from a ladder or scaffolding? but, please don't assume it can't be done just the way you want it!
of course, if you want to move the shed away 2' each way, finish it and wench it back? you can do that also
as always, just my thoughts
take what helps? ignore the rest.