TS, have looked at any of the racks that pivot and lift the bikes onto the roof? I think Draftmaster is one of the brands. Maillotpois has one for her tandem. We need to replace our tandem rack so I'll be doing some research. If I see anything, I'll let you know. Let me know if you find something also!

On the trailer, I think it would be fine. I've seen them. But two things, light trailers tend to bounce around a lot so one bike could mean the thing is jouncing all over the place.

Also, trailers are a pain in the patootie a lot of times - parking, turning around, etc. We haul trailers a lot. It takes planning and we try not to unless except for the times we absolutely can't do it any other way (like hauling drift boats or 10 bikes).