We are grandparents traveling with grandkids (age 13 and age 15) visiting Rome for a couple of full days in mid-May; Friday and Saturday, then traveling on up to Venice Sunday morning. Do you see a problem with taking the train in the morning from Rome to Florence; checking in our bags at the Florence train station; visiting Florence for a 2-4 hours, having lunch, etc; then in the afternoon traveling by train on to Venice? Since we will be traveling thru Austria, & Germany then on to Paris, we are thinking about using Eural passes. Thanks in advance.
There is no reason you cannot do what you suggestion. It requires two separate tickets - first to Florence and then Venice. A Eurail pass generally does not pay in Italy because fare are low and very cheap if you purchase on line to take advantage of either the super economy or economy fares. Might be better for the other countries
With any pass you really need to do your homework to determine if you are saving money. Thirty years ago a rail pass was a no brainer but with deep discounts for advance sales and extra charges for reservations and premium trains the pass can be marginal as to value. Some will argue that a pass provides more flexibility but you pay for that.
I wouldn't say that 4 hours is enough to see Florence. Most people would say that a couple of days are necessary even for just the basics. But if all you have is 4 hours, that will be enough time to walk from the Station to the Duomo and Piazza Signoria and back. Can you devote at least one day to Florence? (depart Rome in the morn. Visit Florence, spend the night in Florence and go to Venice the next day).
Not sure if Eurail pass is a good investment nowadays. It is often cheaper to just buy point to point tickets. If you buy ahead of time you can get big discounts too (although discounted tickets purchased in advance are not refundable if you change plans). Also after the age of 26 I think eurail passes still come only for first class, which I consider a useless splurge since 2nd class is just as nice. You should do some research on the cost of point to point tickets before investing the huge amount required for eurail passes (which don't even cover certain high speed train charges).
Train schedules on Sunday are not much different than any other day. Starting April 1, you will be able to buy a 4-country Selectpass the covers 1st-class travel in Italy-Austria-Germany-France. The main reason to buy a pass will be if it saves money, or if you really want to be in first class, but not so much for convenience. With a pass, you can hop on nearly any daytime train in Germany and Austria (no reservation necessary), but you do need reservations for sleepers on night trains and for faster/longer service to/from/within Italy and France. Italian trains need a seat reservation (usually available on short notice for about $15 per person) and French TGV trains need a seat reservation before you leave home (about $25, seats for passholders are limited). To get started, compare full-fare 2nd class ticket costs using the maps at http://www.ricksteves.com/travel-tips/transportation/trains/cost-maps. See more about train travel in each country using Rick's links on the right-hand sidebar of that page.