Over the past couple of years I have researched an extensive number of low-traffic routes from far away areas like Troutdale, Gresham/Boring, Oregon City, and Tigard back into downtown Portland.
Here is the website for those routes.
A few updates are coming soon. One is a revised route from Tanasbourne
the other is a revised route from the Springwater to SE Clinton
If you have any routes that you particularly like, just email me and I'll see about incorporating them into the site.