1. What does the trip planner recommend? That’s the best general recommendation you’re going to get. Anything more specific requires spending the time to look up each ticket on the individual national rail company websites and purchasing non-refundable tickets well in advance.
2. Adding extra days to cover side trips is usually not a good deal. Buying a point to point ticket for a side trip is usually cheaper than additional days on the rail pass. However, more days will give you the possibility of a major itinerary change (like adding Florence) and will probably be cheaper for very long day trips like your one to Normandy. IMO, Normandy is not a reasonable on-your-own day trip from Paris. Take an organized tour (which will most likely include the train ticket from Paris) if you want to see Normandy as a day trip.
3. Check pricing for tickets on the individual national rail company websites. France: http://www.sncf.com/… Italy: http://www.ferrovied… All of the links are in a sticky at the top of this forum or under “transportation” on the “travel tips” tab. Note that the prices usually include the reservation if it’s required. Try to find a train that doesn’t require a reservation when comparing to the cost of a railpass.

Thanks! We will have to really decide then on side trips. So for Rome-Pompeii would you just get point to point rather than use up a day?

I couldn’t find tours right from paris, they all start in Caen. But I will keep looking

thank you, pass it is!

yay! I looked for a tour from paris and found one for 200 us.

More expensive, but at least includes from paris so don’t need to take train to Caen.

woo

Your railpass will cover the trip from Rome to Naples, if you want to use a day. The Circumvesuvius line from Naples to Pompeii is a commuter light rail train and isn’t covered by the railpass. It looks like the base fare from Rome to Naples for 20,50 euros in 2nd class.