Originally Posted by
axolotl
Here's an idea: You can take a ferry from southern France (Marseille, Toulon, or Nice) to Corsica. Corsica is outstanding for cycling, but it is not a flat island (the east coast is, but it's the only part of Corsica which is not beautiful). From there, you can take a ferry either to mainland Italy or to Sardinia, and then from Sardinia to mainland Italy very close to Rome. In any event, it's a way to avoid both the Italian Riviera and the Alps, though personally, I liked cycling in the Alps.
i sorta did this in reverse as part of my trip a few years ago. i took the ferry from citavecchia (near rome) to cagliari, sardegna, and rode up to santa teresa (or whatever the town is across from bonifacio.) took the ferry to bonifacio, rode up to bastia, took the ferry to nice, rode the route des grandes alpes (you don't have to skip the alps, and this route est vraiment beau!) to lac leman, then rode along the jura (more mountains) to alsace, and took the route des grands vins d'alsace to strasbourg.
if you have the time, and are not attached to staying on the continent, i strongly suggest la corse and sardegna. these islands are stupidly beautifu, and i don't think there is as much bang-for-the-buck scenery anywhere else between paris and rome. i haven't been to the east side of la corse, but i would bet it is far from ugly.
as far as trains go, my experience is rather limited. i think just about any fast train requires your bike to be in a bag, which i think are somewhat pricey and a pain in the ass to carry with you. most regional/slow trains don't have the bag restriction, or at least they didn't. you may be able to just show up at the ticket window and tell them where you want to go and that you have a bike, and they can probably cobble together a series of slow trains to get you to your destination.