I also just got rid of my wodent wheel because I heard they were a hazard, but the fast track just came in and last night I caught ziggy sitting on the side of the cage pushing it, so the wheel was just spinning with no glider in it. Lol this morning I woke up to him running, running, running on it then just holding on and riding it around and around until it stopped spinning.. Over and over and over. Haha! I'm willing to bet he did that most of the night :) it was so fun to watch! :D
I put wiffel balls in there, but they don't care for them really.. They really like those wooden poles that go all the way across the cage (they are really for birds).. Oh and there are a bunch of small fleece squares In there that they just like to move all over.. Idk why, but every morning they are in a different place haha.
Good luck with them! I've had mine for 2 1/2 weeks now and they are just now really starting to warm up.. It took a lot of patience, but it pays off in the end :D