Regardless of source of the problem Sheila, it shouldn't be vibrating so noticeably. Your dealer should take a look at it before some damage occurs.
I am hoping it is something simple the DH can fix, such as loose bolts. The TT has allready been back to the dealer after the first trip out for some minor repairs. We have many trips planned and payed for, so if he can fix something simple and we don't need to return it, that would be best. But of course if it is something that we can't fix or figure out, it will go back.