I also stayed at a hotel... Are you going with kids?
We just went as a couple (it was our honeymoon) but one of our favorite things was the free bus system. I know that sounds stupid, but it's like it's own little tour system. Make sure your camp grounds are on the bus route.
If you are looking for touristy things to do- I recommend Lulu's lobster boat ride (aprox$35) because they do a good job. Look into going at low tide because you will see more. If you look them up online, you can book in advance and they are very friendly.
We also really enjoyed a sunset kayak tour from Aquaterra... enough we went out a few times while we were there even though we are NOT at all athletic.
Strange as it is, our favorite clam chowder in town was from the little fast food style stand advertising ice cream on the right side of the exterior of the aquaterra building.
The thirsty whale also had a grilled cheese sandwich and cup of chowder combo that we went back for three times.
I do not recommend the whale tours. We tried to overhear people as they were leaving tourist events to see what they were saying and ususally the whale tour people were complaining that they were cold, wet and bored for most of the trip.