How to please a very lonely, but very PICKY boy?

So until we can get Pickle neutered, he has had to go into his old cage alone. He still has plenty of outside time with the other boys, and does fine, but as soon as there is food involved, he flips his wig. So he's having to live alone for the time being.

But the poor thing, he just looks so BORED. I can't figure out how to get him stimulated, because he's the pickiest little bugger ever. He doesn't run on his wheel. He won't get in hammocks. He doesn't like his jingly bell. He's so smart that most puzzles only stimulate him for about ten seconds until he figures it out. He doesn't even like to hide in huts! I just don't know how to keep him occupied.

Any suggestions on how to keep this picky little Pickle occupied until I can scrape together money for his neuter?

Hang a roll of toilet paper in his cage.
Give him a snak shack log to climb in/on and chew
Hang a medium edible paper tube for him to climb in chew etc
Give him a box with a couple of entrances he can enlarge, full of pieces of packing paper
He might like to destroy and build nests out of paper bags