When we went in 2001, you had to book your excursions on the train from Anchorage (if you're on that itinerary). The flightseeing tours to McKinley booked quickly, but we had clear weather and we heard they were great. We wanted to book the heli-hike, but it was filled.
We got the jet boat tour while in Talkeetna, not anything to write home about and then we booked a float and fishing trip. Not recommended. It was ok , but it was salmon snagging, not fishing and the float trip was short.
There are some neat trails around the lodge to walk around as well and you can spend some time in Talkeetna as well.
If you want to get out, the flightseeing/hiking is the best bet.
Note - If you are an early riser (before 6am) and you want coffee at the lodge, better bring your own!