Like the Ovens, Headstrong Buttress is a crag near Red Lodge that offers single-pitch climbing (though there is one two-pitch route). Unlike the Ovens, the rock is granite (vs. limestone at the Ovens), there is about an even mix of sport and trad (vs. all sport at the Ovens), and the approach is about 15 minutes of moderately steep uphill hiking (vs. about 15 seconds for the Ovens).
While not anything truly daunting, that longer, steeper approach probably serves to keep large groups away most of the time whereas the Ovens can frequently be busy due to the easy approach and the easy access to top anchors.
Another plus to climbing at Headstrong Buttress is that although it is seemingly a stone's throw from the busy Beartooth Highway, it is high enough above it to yield excellent views and provide a sense of escape from all that bustle below.
Notes if you are using the Mountain Project page, too--
Head west out of Red Lodge on the Beartooth Highway (U.S. 212). After a mile, you will pass a turnoff for the Westminster Spire Camp on your left; just past it, also on the left, is a large pullout. Park there. Headstrong Buttress is almost directly across the road and uphill.
There is a climber's trail if you can find it; at times, it disappears among deadfall from a fire. Just study pictures here and/or on the MP page and follow the path of least resistance and you'll get there.
Ultimately, you should end up at or near the base of the 5.5 slab routes or Voyager.
From Left to Right:
Climbing the first pitch of Voyager supposedly puts you in position to access anchors for most if not all of the routes to its left.
Despite a couple of inaccuracies on the MP page, the page is overall a good resource because of the photos with route topos on them. I cannot vouch for or against the beta on anything other than Voyager/Voyeur/Class Clown/Hot for Teachers because I was out for a casual morning and with a newer climber and those routes were the only ones I climbed.
Spring through fall.
Sleep in your car at the pullout (not sure if that's legal, but it's what I did) or turn onto one of the nearby Forest Service roads and look for campgrounds or dispersed camping.