loop ride from Portland
GM, given your predeliction for heading east I'd recommend something like:
- out the Gorge to Hood River - the Dalles
- the Dalles south on hwy 197 to Dufur - Tygh Valley
- Tygh Valley west to Wamic - FS 48 to Barlow Crossing Rd (FS 43)
- FS 43 west to Hwy 26
- Hwy 26 north a few miles to Timothy Lake turnoff
- FS 42 to Timothy Lake, then down the Timothy Lake outlet* to the Clackamas River/Ripplebrook Ranger Station
- Clackams River downstream to Estacada, Portland.
about 6 days, 7 if you're leisurely?
* the old road (closed due to washouts) is paved the entire way but involves a cople of fairly easy bike portages - at least they were easy a couple years ago. Essentially, a paved bike path almost all the way down to Rippllebrook. It's FS road 5820, just norht of the Pine Pt. dam -- you can see it on the Mt Hood National Forest map.