That's what I'm working towards, even if it is only to France.
FWIW, when I started doing the trip, it was a no-brainer in convenience and financial terms to do the Flybe Dash-8 from Exeter to Paris CdG and train it from there: the PITA bit of being in the SW is getting to and across London for Eurostar, plus the high price of Eurostar.
That said, I did Lille to Exeter for £110 this week, and as flying from Bristol is also a PITA (especially compared with the discontinued Exeter-CdG option), making doing it in a day from door to door in a day more or less impossible, once I've factored in an overnight stop, I'll be checking out Eurostar-Lille options, particularly as I can TGV it straight down to Valence from there. The slightly hopeful development is that Virgin will be competing with Eurostar in the not-too-distant future, so that ought to put a cap on prices, or even dive them down somewhat.
I think my next stage would be one-month stays, once I've stopped another part of my work commitments. It's just so lovely not having to think of the end of the break as soon as you've arrived.