Don't you think bike theft is a possibility most any place?
Anyway when I took my bike over there, I walked my bike to the spot I wanted and locked it up -you can lock it to your partner's in front or back of yours. etc.
When you walk on the island, you walk your bike etc./or ride where it is safe for you or other people.
I do not know the charge for renting bikes but a long time ago I did rent one. It was ok -
If you want to have a lot of fun and you x country ski look up the festival that takes place in February ( I THINK )
You can drive to St. Ignace. Stay at a nice bed and breakfast. Then drive to the airport and fly over to the Island. The Poker Run is soooooooooo much fun. Then they have a chili cook off in one of the local bar/resturants.
There is just one church there but I went and it was nice. People came on snowmobiles and skis'.
Have fun! Barb