Map needed to make route from tracks of bike trail

I did a bike ride mostly on bike trails (not roads) around Redmond, Washington (East of Seattle).  I want to make a route from the tracks, but when I do I get a bunch of crazy lines from places well off of the trail to the waypoints.   Looking at some other posted questions and answers I think the problem may be that it's trying to make a route based on roads, and I was not on roads.  Do I need to download some map that has bike trails, and, if so, where do I get it and how to install?

Macbook Pro

Garmin Edge 530

Basecamp 4.8.12