Paper towels shouldn't be a big part of a rabbit's diet, though. The paper is bleached to make it white, so I ought a roll of brown paper & tear Honey off a piece as needed. She mostly tears it rather than eats it.
i put it on the floor of the nic cage for traction but little bun seems to like picking it up and moving it around and i think may be ingesting a little
Might try some cardboard--ours love to chew it, throw it around, and lounge on it. As long as it doesn't have photo quality pics which are plastic, it's alright for them.
another thing i was thinking of are the card board that light bulbs come in they have a cool traction area on the inside of them to stop the light bulbs from slipping out