Cure your post-wedding hangover with a day soaking in Mt. Princeton's geothermal pools. Day passes must be purchased day of on-site or are included with your room.
BV is known for its whitewater rafting. The river will be a little slow at the end of the season in September, but it will definitely still be a good time.
There is no shortage of epic hikes around BV. Check out https://www.alltrails.com/us/colorado/buena-vista for more.
Biggies is well named - they have the biggest sandwiches you've ever seen!