Itinerary

Um, have you looked at how long a train from Florence to Barcelona would be? Why return to Barcelona at all? You could fly multi city into Barcelona and out of Florence (connecting to a US flight at a European hub city). Even if it's more expensive than a round trip ticket, it's likely worthwhile when you factor in the cost of that train trip, in both dollars and time.

I've lost track of whether you've been to Barcelona before and whether Sept. 19 is the day you fly in from the US/Canada (in which case I wouldn't count it as a real sightseeing day in Barcelona). It's also not clear whether you are training from Florence to Barcelona on the 11th or 12th. If you're traveling on the 12th, you have just the one Barcelona day at the end of your trip to add to Sept. 20 and 21 (and one of those is your Girona day). So how many real, full days do you actually have in Barcelona? It can't be many.

Overall, my impression is that you could use more time in Barcelona/Girona, where there's a lot to do, plus multiple good day-trips, as compared to three full days in Valencia which no doubt has things to see, but figures on few if any top-places-to-go-in-Spain lists. I'd drop Valencia in a heartbeat.

There's plenty to do if you remain based in Barcelona and Girona until you fly to Genoa for your cruise, and that is where I'd spend my time. Day-trip to Montserrat from Barcelona. Day-trips to Figueres (if you're interested in the Dali Theatre and Museum), Cadaques and Besalu from Girona.
Girona itself deserves a full day (2 nights even without side trips).

We come back and forth to Barcelona because that is what we're Landing to from Florida on September 19th and departing from Barcelona on October 13th I have also already purchased a ticket vueling. Com from Barcelona to genoa where are cruise ship departs... Those I cannot return...
So I guess maybe I should just shorten the trip to Barcelona instead of 8 days to 4 and spend for in Girona Spain?? And take Valencia out?

Yes, dump Valencia.

The amount of time to spend in Barcelona vs. Girona depends on what you want to do in each place, including side-trips. I don't like short hotel stays, either, but to me there's nothing magic about 4 nights instead of 3. Barcelona has far more sights than Girona, and it is larger, so there's time to be spent just getting from place to place. Without knowing what you want to see and do, I'd say I'd want to split 5/3 rather than 4/4. Remember that your first day is a sort of sleep-walking day. As a matter of fact, it would make a lot of sense to arrive in Barcelona and hop on a train to Girona that day, making use of some time when you won't be a very productive traveler, anyway.

Now, if you are uninterested in modernista architecture and don't mush like large, busy cities, going 4/4 would be logical, but that would give you only 3 real sightseeing days in Barcelona, which is terribly short.

We have been to Barcelona before... We did the Cathedral also Montserrat ... Kids were small so we ate a lot...

Well, if you're not ready to return to Montserrat on this trip, that will save you the better part of a day.

Are you sure you want to do train from Florence to Barcelona? It looks to be a 16-18 hour trip with multiple transfers.

Florence-Barcelona by train takes 14 hours and 3 connections, only getting you there in one day if you depart at 6:43 a.m. So I'd still be looking at flights from pretty much any Italian airport - could be Florence, Pisa, Bologna, or Venice (if you switch the order of visiting). Switiching the order to Genoa-Florence-Venice also saves an hour of train travel within Italy.

Didnt think getting back to Barcelona was so long. What about I do change it around and do Florence and Venice after we get to Genoa.. And then fly back to Barcelona? I already did the one way from Barcelona to Genoa do you think Vueling would accept adding it 2 ways?