What do you enjoy doing? And how will you travel once you’re there?
I have two suggestions based on experience, both of which involve taking a train out of Nice.
There’s a fabulous train going out of the main station towards Torino through the Bas Alpes. Sospel is a small town with some accommodation, lots of riding & waking around. There are other towns with stations along the way, some of which are fabulous. Breil & Tende may be on the line.
Edit: the train has half-carriages set out for carrying bikes. There will be bags of space if you’re planning to ride there.
There’s a narrow-guage railway running from a separate station, going NW through some lovely countryside. Entrevaux is a tine town which might suit you. Check them all out.