I have a cervelo RS. It's not the fanciest by any means, but it's a racing bike - carbon fibre frame and seat post. I didn't think there would be a problem with putting racks & panniers on it, but there was some vitriol on cervelo message boards about the idea of putting packs on one. I wasn't sure if this was just from stubborn traditionalists, so I checked with a mechanic at the shop I bought it from and he thought it would be bad for the seat clamp - so even if I switched out the carbon seat post for an aluminum one the seat clamp wouldn't take the strain.
Anyways I'm obviously still in the very early stages of planning and am open to all options (other than buying a new bike). I agree that having a car transport gear would detract from the experience, but I'm just trying to cover my bases (so if anyone has suggestions on that end still would love to hear!). It's a relatively short trip (5-6 nights) so I know I could pack light.
If I stay at inns, purchase my meals (indulgent, I know, but trying to keep things simple for my first time) bring one change of clothes and the necessary bike maintenance tools, can I get by without panniers? I.e. with a really large bento box and saddle bag? Might have to forgo rain gear but it would be warm enough not to really matter, I hope.