How level are Southeast Michigan metroparks
 

I ask as far as setting up a double crank on a road bike, with 12-27 10 speed and 50/39 crankset. The gears are not that low, so I'm wondering if hills and elevation-changes would be an issue for such a drivetrain in Southeast Michigan.

The parks closer to downriver are all pretty flat. Lets put it this way: I have a 50/36 and a 11-23 and I never use the small ring.

I think you'll be OK with the 39/27.