well I’m back from said location so I might as well answer my own post in case it proves useful for others.
Firstly – it’s a beautiful area, certainly quite busy and geared up for the tourist trade around the lake but not tacky, over priced or too overdeveloped. We stayed in a campsite in Lathuile which was busy but had a good friendly atmosphere – large contingent of families from the Netherlands and France and a few Brits, Belgians and Germans in the mix.
The lake has a great bike path along the western side that runs the full length separate to the road, on the more scenic west side it is not fully joined up and has a few narrow road sections so less suitable for family riding.
As far as the riding goes, I hired a rather tasty Open Up gravel bike from Basecamp in Talloires for an afternoon – not that cheap but wanted to have something nice to ride and followed a route around the the western slopes up the Col Du Forclaz and taking in some forest road in the mix. There’s apparently quite a bit of gravelly stuff to be had and I’d like to explore some more on a return visit.
For road riding it looks like a great area, my impression is that there are plenty of good climbs like Forclaz, Tamie and Semnoz that are not as arduous as some of well known alpine cols but still challenging.
For MTB, I’m not so sure. The only stuff we really saw was in La Sambuy which has chairlift access. I got a tourist map with ‘VTT’ routes marked but it wasn’t clear if they are forest road or more singletrack type. Anyway, it’s a lovely spot and I’m sure we’ll be back – this time with own bikes in tow.