I think people generally think of southeast Michigan as being pretty flat. Growing up we drove every summer it seemed to visit relatives in Omaha. That whole ride was flat, at least until you got to the Missouri River and then everything was hilly. In fact, I never understood the road signs that say "Bridge May Be Icy" until the first time I drove an hour into Pennsylvania.
We don't have the rolling terrain like Pennsylvania and West Virginia. But this area is by no means flat. That is one of the bigger challenges I'm facing when I go out riding. Consider Orchard Lake Road. It slopes fairly gently most of the way north from 14 to Maple. That's the easy part. Maple to Walnut Lake is another story - it starts sloping up, then a bit of a downhill by Orchard Lake Middle School. You then hit a fairly steep up hill that crests about a 1/4 mile south of Walnut Lake. One time I continued north past Walnut Lake. I don't know how I made it up the hill to get to the High School. Walnut Lake definitely has ups and down from Orchard Lake towards Drake, and Drake does too, especially between Maple and Walnut Lake.
For now, I'm avoiding Maple between Middlebelt and Inkster. That has some pretty steep ups and downs. It has sidewalks most of the way, but not for about a quarter mile heading east from Middlebelt. I'm not confident enough to ride on a major road for that long.
I don't think you notice these hills as much when you are walking. I definitely noticed them when I ran, but I notice them even more now. When you are walking or running, you just have yourself to push up those hills. But when you are biking, you've got the weight of the bike to push up too.
The bike paths don't make it easier - they seem to have more extreme ups and downs the major roads. I'd like to have a conversation with whoever thought that was a good idea.
For now, I'm handling the hills by downshifting to lower gears. I'm making it up them, but every now and then I'm not sure if I will. I'm hoping that as the weight continues to drop off, and especially if I get a lighter bike, that I won't think twice about tackling a hill.