Travel Paris to Lisbon - Family of 5...

Paris is very remote from Lisbon and train connections are difficult between Portugal and Spain and Spain and France. Cost aside, unless you fly, you'll spend over 24 hours on trains and in stations getting to Paris. If you go to Paris, your best option is to fly. Discount airlines can make that a relatively inexpensive option and likely much less than the train. The next question is why you are visiting Paris if your vacation is in Portugal? Have you considered traveling in Portugal and Spain?

We want to take advantage of being in Europe... Paris is high on my family's list of places to visit. I thought the train would be good so that they can see the countryside - my kids are accustomed to long trips by car - this past summer we drove 6500km (no complaining)... maybe it would make more sense to drive.

Carol,, with only one week, I would fly. Your kids won't see as much as you think on the pay highways,, and the secondary ones will add days to your journey. Flying is cheap and fast,, look at flying on Vueling,, if you book well in advance you can get a great price. Gas is EXPENSIVE and so is a one way car rental,, plus getting a car big enough for five ,, not easy or cheap. Rent a car when you get to
Portuagal to tour around there,, you certainly will not need one in Paris and can take a daytrip or two out on the trains to give the kids a train ride(recommend Versailles).

If you had about 4-5 days each to get to and from Paris from Portugal, driving would be a wonderful thing to do. There are a multitude of things to see between the two. But to just efficiently get between the two cities would be a very expensive and long proposition - it's a VERY long distance (Spain and France are two of Europe's largest countries). If you take the train, you'll mostly see nothing. At least one part of the journey, and likely a second part, will be overnight trains. The rail connections between Spain and France are getting better but the options are still limited. One idea if you have the time is to take the train to Paris with overnight stops in Madrid and Barcelona and then fly back to Portugal. Or fly open jaw to Portugal and return home from Paris.

I must agree with flying as the best option. Three of us flew Paris/Barcelona for 31Euro each a couple of years ago and at the end of this month (October) we are flying Gatwick/Barcelona for 116Euro including two bags. If you travel fairly light and prepay for baggage, there really isn't another option as economical and timely.

Thank you for all your suggestions. I think in order to give our family the best Portugal experience, we will skip the Paris part (I am sad about this). We will just have to start saving for another European holiday...
It is pretty funny that we are sad and yet we are spending 3 weeks in Portugal - time to switch up our mindset - bring on the olives!