Try Tina and Francky Moranval at bandofboarders.net and/or Didi Haase at Snowlegends in La Grave.
I've ridden with all 3 (and couple of different guides of Didi's) and they're all fantastic in slightly different ways. Didi's guides are qualified guides, so they can take you on glaciated itineraries, Tina and Francky are instructors, and are good with technique, allbeit in a french style! they've all got plenty of stories, Didi especially.
Amazing area, loooong runs - 2150m top to bottom. It's all off piste at La Grave, bar a couple of blues on the Glacier at the very top. Great place to try out different boards, especially swallowtails. I rode a 185 swallowtail for 9 days and it was a really great experience, amazing in powder, obviously, surprisingly easy to handle, even in tight stuff, and rewards a smooth technique, so getting back on your regular board afterwards, you really notice the difference it's made to your riding.
Sort your own accomodation (dorm style hostel to fancy hotels available) join groups with Tina, Francky and Didi, depending on conditions and what you fancy.
Second digby's recommendation of Fernie W.A. Great set-up, rest on the way back up, great skiing, especially if you like trees!
And getting fitter is going to make such a difference to how much you enjoy it. I'd really do as much as you can. It takes a fair bit out of you, and being stronger for longer means you'll ride harder, learn more, fall less, enjoy it more. Once you get tuckered out and start making silly mistakes, it can be a sharp downward spiral of falling, getting cold and wet, struggling to get up in deep snow, getting more knackered more quickly, falling more, enjoying less...
I probably hiked for about 20 minutes in the 9 days, and I could have avoided even that. I was still absolutely toasted after riding hard all day, though!
Enjoy whatever you do, though!
