As I got to that stage, I found that I could not afford either the time away from work, or simply the cash for one long tour away. Instead, we used to go for lots of 4 day trips. From Cardiff the first stop was always the Channel Islands to fill up with cheap fuel and breakfast. I don't know what the situation is at your club (if you are hiring), but they would always pay us back at the 'home fuel' rate, which meant that if the fuel at Cardiff cost £1 per litre (a while back), and the fuel in Alderney cost 25p per litre, we would gain 75p per litre towards the cost of flying. Don't forget that you can claim the tax back on any fuel that you export, as well - brings the cost down a little further.
We would then spread the map out along the wing, draw a circle at the 2-3 hour distance and then decide where to go for lunch. After lunch we would do the same to decide where to go that evening. Absolutely no forward planning (other than weather and Notams) meant that we had to get very good at map reading and accurate VFR flying. 2.5 days each way should give you a really good opportunity to see a lot of France, or hack off East - the decision can be made on the day when you see where the best weather is. Go for it - you will remember it for ever.