I live in rolling terrain of Southwest Portland. I've commuted to work by Multnomah Blvd to Barber Blvd, a route that was once a rail line and then an interstate highway. The rolling has been taken out of these.
Neighborhoods are divided by creeks and canyons. They have many dead end streets where one hood fails to connect with its neighbor.
Footpaths or bike trails sprout out where cars can't go. Folks find a way through even when the road doesn't.
Open Street Maps are very good at showing these paths and trails. Google or Apple maps less so.
If a road takes a dip there is a creek nearby. I can now name many of them and know of others nameless.
The USGS and Oregon integrate considerable information about stream flows. See Environmental Linked Features
Many trails are almost invisible from the road. Even by bike I must move slowly. I see more when leaves have fallen.
Steep trails show signs of mountain biking. Some are so steep I have trouble walking.
In many places a small stream will go underground for blocks. I'll see more trees where it surfaces again.
Much of Portland is built over streams which still flow underground. Culverts Threaten Fish
I've found homeless camps ranging from a idilic creekside to a trash dump. I've met folks but never been confronted.
I've found unexpected benches and other comfortable places to pause and enjoy the outdoor environment. Comforts I Have Found
I'm wishing I paid more attention to the trees I've encountered. They are often mapped in park surveys. Trees to Recognize