Toby,
Norm from Ottawa is very knowledgeable about train and bus service in Spain. I sent him a PM yesterday asking him to post a note on this thread. He usually answers right away so perhaps he is away from home. In the meantime I'll make some suggestions with which I think he will agree.
First of all, don't buy a railpass. Here's why. Bus service from Barcelona to Pamplona is not all that much slower than train service and it is a lot cheaper. Taking the train from Pamplona to Paris means a long ride with several connections. And it won't be cheap. You'd be better off taking a morning bus back to Barcelona and flying from there to Paris on Vueling, a budget airline. It will be cheaper as well as faster. Book the Vueling flight ASAP to get the best fare.
For Paris-Amsterdam you will take a Thalys high-speed train, not a TGV. The standard fare is pricey so book NOW to get a discount fare. Go to www.thalys.com and choose France and English. Click on Paper Ticket and choose France as the country in which you will retrieve it. If you get a discount fare, you can print the ticket yourself. For other fares you can pick up the ticket at Gare du Nord in Paris.