If you’re looking at local area in your definition of “environment”, I don’t think any SA holds a candle to USAFA.
For biking you have the Greenway Trail which goes right by the USAFA. I’m not sure how far it goes, but eventually the plan is for it to stretch from Wyoming to New Mexico.
Of course the Rockies have outstanding camping and hiking. DD spent the COVID semester in Colorado and spent most of the time hiking and camping. She even did the one day Pikes Peak run/hike.
In the winter skiing and snow boarding.
USMA probably has the best fitness culture if that’s what you mean by environment. I don’t think you can go four years at USMA not doing several ruck marches and as far as I know it’s the only SA where doing an obstacle course is a graduation requirement. While USAFA is at the foot of the Rocky Mountains, USMA is built in a fjord so you have a tough time finding flat terrain. On the down side bike riding at USMA is tough. Lee Gate to Thayer Gate is about 3 miles each way and I think many bikers just do that loop. The more adventurous leave post, but most of the roads off post are not bike friendly.
But if you are into fitness you won’t be out of place at any of the SAs as they all emphasize fitness to some extent.