Mountain biking is available at Mammoth Mountain with bike rentals.
There are so many hiking trails in the area! Some recommended hikes are Thousand Island Lake (hard), Convict Lake Loop (easy), Devils Postpile and Rainbow Falls (easy), Shadow Lake (moderate), Yost and Fern Lakes (moderate).
Hot springs in the area include Travertine Hot Springs, Rock Tub, Crab Cooker, Hilltop, Wild Willy’s and more!
https://mcgeecreekpackstation.com Beautiful riding trails.
June Lake is right next door to mammoth but a much smaller town - also has beautiful views, hikes and a great brewery!
The Tioga Pass entrance for Yosemite is only 45 minutes from Mammoth! Keep in mind the valley is another few hours into the park.