I recently purchased my first TT and found a pre-purchase inspection sheet on here that someone posted in a PDF. For the life of me I cannot find that sheet, and properly thank them. I spent 9 hours at the dealership, of which 7 were me doing the inspection.
I told them I would not sign anything until I went thru the TT with my sheet, which helped a immensely. And while I was inspecting it, the tech was showing me how to operate the various things on the TT, and he was very patient (at least until the 7th hour, but I cannot blame him). I found things wrong with the TT and they fixed everything they could while I was there. The only things they could not fix was a small scratch on the outside and scratches on the woodwork in the bathroom. And I still missed a few things (cabinet door latch, outside 110 outlet, and a light switch that needs to be replaced).
IMO I would not buy from a dealership that will not let you do a thorough inspection prior to signing any paperwork.