In reply to j3z:
Don't let Uk public transport dishearten you. We have the crappest network in the whole of Europe.
France etc tends to run a lot smoother, and most train/bus stations have enough multi-lingual staff to be able to deal with any questions you have. Might be best to get as much info as possible about your travel route closer to Paris as you can get some confused francophone bus drivers further out but as long as you have enough info for your links etc you'll be fine.