Hmmm, sounds like I have some options. I'm a bit concerned that a trainer will damage my skewer or nuts. Thoughts?

Rollers seem like a good alternative, but I have no experience with them. Is there any way to change resistance on them? I'm also happy to improve my balance and handling, but indoor training is really about keeping up my fitness for long summer rides. Can I get the same workout on rollers that I get on a trainer?