Logistically, 2 nights could be hard to pull off. Check the NPS web site for IR and the boat schedules. Living in Michigan I'm not familiar with the boats that leave from Minnesota. There is also the seaplane option. Another thing to consider is the late season weather, boat and seaplane schedules can get, umm, flexible. There may be a day or days where the boat/plane might not be able to travel because of storms. Lastly 2 nights is just enough time to scratch the surface, as mentioned IR is the least visited Nat'l Park but I think it is the most re-visited. Two nights is just going to whet your appetite and leave you wanting more.
I don't consider an IR trip expensive, just over $100 for the boat and the $4 per day user fee. Cheap when compared to a flight.
As for hearing wolves howl you sure don't need to go to IR. Michigan U.P. has plenty, I've seen more than usual black bears this year too.