Solo camping Yellowstone and ? in September

Heading to Yellowstone in September. First solo trip outside western WA since my wife passed 3 years ago and damned if I can come up with many good ideas myself. Have 5 nights reserved at Fishing Bridge, but not sure where to go after. This will be my 4th or 5th Yellowstone/Teton trip and I have up to two weeks to kill.

Trying to decide if I go south through the Tetons after Fishing Bridge closes on the 16th or if I go north through Red Lodge and maybe to Poulson.

Any ideas for an introvert on the road alone?