Which parks can I use the pass at if I pay the $40?

The pass is only good at Metroparks, you can get the list of parks at the website

All 13 Huron- Clinton Metro Parks

Huron Clinton parks

Your past is only good at metroparks in Tri-County area

only the part that you get it from

All metro parks, lower Huron, willow, Kensington, stoney Creek, lake saint Clair shores.

I agree with Will Smith and Ashley Jones. Lol