Ablon is beautiful. Longish approach walk, which seems to be uphill in both directions. But worth it. You can van camp right next to the tourist info place at the top of the col, and there's a toilet in there too. The climbing is vertical, old school, and hard!
Balme de Yenne is very impressive, and has really good climbing, but was a bit too roady for our liking. Excellent 6's on the left for warming up, and loads of really good 7's. We only stayed for a couple of days.