Originally Posted by
tarwheel
Here's another idea. The Adventure Cycling Association has a Portland to Crater Lake trip planned for August 2-16 this year. Contact them and see if they will share their route. They would probably be more than willing to do that, since that's one of their missions -- developing cycling routes.
Portland-Crater Lake Loop | Guided Tours | Adventure Cycling Association
Just comparing the itinerary for that trip against their
ACA interactive map, it looks to me like their route is going to look a lot like this:
http://mapq.st/1lzl7nZ
Edit: Route without Windigo Alternate:
http://mapq.st/1pR0mby
I'm sure the $16 for the
Sierra Cascades Section 2 maps is money well spent. It's not obvious to me whether they would route along OR-140 or US-97 into Klamath Falls, as the ACA Sierra Cascades maps south of Crater Lake route west toward Ashland via Butte Falls. Maybe some with local knowledge could chime in about scenery/traffic/shoulder quality.
(It should be noted that Google maps is a complete and utter
mess when it comes to routing a trip like this, using either bike or car directions.)