asking the RS universe for your opinion on this transfer from Barcelona to Nice

7 hours from Barcelona to Nice sounds optimistic. And if you're comparing the travel time for train vs car, remember that the time on the train is time you can use for other things and you don't need to make bathroom stops. And a Spanish rental car will probably not have a Crit’air-sticker.

Another option is to take the train but stop for a night somewhere along the way to break up the journey. There are many towns that are worth a stop. If you still want to drive, start by taking the train across the border and rent the car in France, that will save you the cost of returning a Spanish car in France.

A train 90 minutes after docking is foolish.

The ship has to be cleared by the port authorities once it has docked (assuming it is on time), then there will be a line to get off the ship even if you are self-disembarking. Potentially a passport check. Then a taxi from terminal to railway station. Who knows if there will be a line waiting for the taxis.

Will you have already spent time in Barcelona ? We spent 3 nights after our cruise before flying to Nice. Regardless, I would fly but not so soon after docking if you go that first day

I agree with Badger about the driving time. google map has a time spread of ~6-9 hrs. Add a lunch stop .....

Planning to be on a train 90 minutes after the boat's scheduled arrival time.... 'foolish' is putting it kindly

If you are committed to sleeping in Nice the day you dock, the airplane, by default, is the practical choice.
The 1:50PM flight ( ~90 minutes) looks like a winner to me.

Your trip, your choice.

Fly, fly, fly. The second busiest travel weekend of the year. That autoroute from the border to Montpellier is already a mess on normal days, a parking lot on weekends. Fly. Drive only if a strike is called, but take a train to Perpignan and pick up your car in France to avoid big cross border drop off fees. Fly.

all the pick seat fees, luggage or one way car rental its all about
$1k plus or minus a few dollars for all 3 options

On July 12 there are 3 Barcelona → Nice direct flights.
Including an Easyjet at 7:30 p.m. for €27/person (without baggage) and a Vueling at 2:25 p.m. for €58/person (without baggage)

You also have a Barcelona → Nice by train, departing from Barcelona at 1:09 p.m. at the current price of €136.80 per person

Fly unless your luggage is to heavy -- I remember that Easy jet when we last flew it -- quite a few years ago-- had limits on luggage that could not be exceeded even by paying more. It was not crazy tight but you had to meet their requirements and if you are hauling too much stuff, there you are.

thank you all for the common sense responses

as they say in the NFL upon further review we think we will take a train to Madrid 2 days and fly from there

my wife always reminds me I do get ahead of myself when I'm in the dream up the plan phase