This summer I'm going to be traveling to the East Coast. At one point in my trip I will need to get from Montreal to Kingston NY (not Kingston Ontario). In Kingston I'm going to be at a camp in the Catskills for a week, and then return to Montreal. I have no car and am trying to figure out the best way to do this.
I see two options:
1) Greyhound or other bus service. There seems to be no direct way to get to Kingston by bus. Also once in Kingston, I will still have to cab to the final Camp location, which seems to be a bit of a ways outside of town.
2) Rent a Car This would obviously be much more convenient, but I am concerned about the difficulties of bringing a car across the border for a week and hidden fees and such.
Does anybody have any insight into this, particularly into cost differences? Are there any other travel options I might be missing?

