I went with wife and teenage son by train to Barcelona.
We drove to Lille via Eurotunnel and stayed at a budget hotel, leaving the car there the next morning when we took the nearby metro to Lille Flandres station.
This was because Eurostar and the train from home in Gloucestershire would together have been the most expensive part of the trip, and we could also bring back a decent quantity of wine!
Lille to Paris by TGV then Paris to Perpignan by TGV and a night there in a hotel near the station.
Lovely, intriguing chat with fellow travellers and a chance to explore a French Catalan city that evening.
Train next morning to Barcelona, which I think had come from Switzerland.
After a week's stay we reversed the trip and didn't feel the slightest bit travel-weary when we got home. We had to juggle around with train times on the SNCF web site to get best fares, but being accompanied by our young son seemed to give us cheaper fares than if we had only been a couple.
Roll on St Pancras to Barcelona without a change!
Send your feedback or queries to firstname.lastname@example.org