As I can only really speak of Paris at this point I’ll say it is an excellent place to get around; especially with the integrated Metro/RER/SNCF Transillien transport systems! There are so many options of how to get into France nowadays that I guess it’s all about personal preference; and how long you actually want to let the journey take to get to your destination.
Being able to speak a little French always helps but I found most people in the touristy areas spoke quite decent English.
SNCF Transillien is Paris’ local network which interlinks SNCF trains on 14 suburban lines throughout Paris, along with a plethora of night bus services throughout the City.
Train times and Tickets (Paris)
Transillien Network Timetables can be found on the Transillien website; unfortunately they can only be found when using the site in French for some reason. It gives timetables for the local RER services within Paris also; just hover over the letter of the relevant line that you require and it will show you the timetables available; once you click the icon a map of the relevant line is displayed, along with the current timetables, in PDF format.
There are various tickets for travel within the Paris area; all governed by zones (like the London Underground). The three major tickets being the Paris Visite Pass, the Mobilis Day Pass & the Ticket t+; details of all the Paris Travel Tickets can be found on the Transillien website.
Rail & Metro System Maps for Paris are available on the Transillien website.
Train Times and Tickets (General)
Booking train tickets both within or cross border into France can be done on the SNCF website.
If you’re choosing to use an Interrail pass, either for travel just within France, or to pass through France, all the relevant details on the passes, including the different types/lengths of validity available, can be found on the InterRail website.
Finally travel in Europe can be made a lot simpler by using the very, very, helpful smartphone app courtesy of Eurail. This app is available both online and offline and is always up to date (well it has been for the countries I’ve used it in; including for any planned engineering works); for me it was an essential part of my travel in Europe. This app is linked to the Hafas system, which countries like Germany, Austria & Switzerland use for their train planning online tool. Eurail has done what the individual countries haven’t though and made it available offline.
I found the “Visit Paris by Metro” smartphone app to be very useful; it has offline maps of both the City & the Transport network and gives details of all the Paris tourist attractions. It will plan a route between any two places in Paris, again offline, and give you very detailed transfer details between the various transport networks which are far easier than looking at maps at stations and trying to remember where you’re going.