Castles at Besano (main Adige valley) and the Trento one if they let you see the frescos in the turret. Up the valley north of Riva: via feratta at Drena, Sarche has a cantina (wine cooperative, nice food too). Nearby are the Brenta Dolomites, if you can organise a jeep taxi up from Dorsino up to a hut there’s fantastic walking there, scenery every bit as dramatic as the eastern Dolomites but without the crowds.
We used to go to the pizzeria in Dro to avoid the crowds.
The mountain biking is relentlessly stoney and it takes a while to adapt.