Through-biking the Ghost Grades of the Deschutes
I'll tell you right now, through-biking these grades requires a resourceful and determined rider with multiple outdoor skills and plenty of nerve. I've done the legwork - here it is.
There are 95 miles of abandoned grades in the 107 miles from Madras. Remember the lines combined for 12 miles between North and South Junctions, and that's still an active railroad line - absolutely off-limits, no trespassing nohow.
The locked Deschutes Club gate
Below North Junction, another 11 miles are blocked by "the Deschutes Club", which forbids any wheeled vehicles on the grade. That's a total 23-mile blockade.
You have two choices - climb out from Trout Creek to US 97, and get back on the grades at Maupin - or carry a pack-raft on your bike and float the river around the blockade. If you survive the rapids, you can then land at Nena, or any other place you like, and ride on north to Mack's Canyon at River Mile 25 (25 upriver from the Columbia).
Between RM 25 and 20 are badlands. Several trestles are out. The abandoned sections are like islands in time, ties still embedded, sagebrush and rockfalls making the way nearly impassable. It's do-able - see GlowBoy's account from the keywords page - but I don't think you'd ever want to do that again. From Mack's you can raft it, or rough it, or turn around back to Maupin.
Below RM 20 it's an easy off-pavement ride along the grade 17 miles to Deschutes State Park.
I reckon the whole trip could easily be done in a week from Terrebonne to The Dalles. I suggest if you spot a vehicle at the south end, use Smith Rock Storage in Terrebonne, where I got secure parking for $30 a month. For some reason, Madras doesn't allow open vehicle storage in its city limits. In any case, from Terrebonne it's just 3 miles to the Crooked River Gorge, and an easy day's ride through Culver and Metolius to Madras.
You could also spot a vehicle at the BLM's Trout Creek area, do a long day's light-load round-trip to Madras, then float on downriver.
On the north end, you're on your own. You can pay a fee for "overnight parking" at the state park, but it's unwatched. You can probably call around and find secure parking in The Dalles. It's probably cheaper across the Columbia in White Salmon, but be advised the Hood River bridge is barely wide enough for two modern cars - no room for bikes. You can ride across the river at The Dalles or Biggs bridges - or raft across. Barge traffic seems to stay in a narrow channel.
Another alternative is biking back to Terrebonne through Grass Valley and Moro, and maybe taking in Shaniko.
There is your mission, should you decide to accept it. When they fish you out, tell 'em "Joe sent me."
By the way - I should mention I've ridden the route, but haven't floated the river. When I tested my $45 Walmart raft en route at Lake Simtustus, it carried me, my bike, and touring gear on the lake, but I wouldn't give the thing 50 to 1 on surviving. 28 miles on the river, without modifications I couldn't do in the field, on the fly. I was due on the river Monday, giving me 2 days - one of them a Sunday, when nearly everything in Madras is closed. No rush - I decided to back off until I could do it right.
As far as I can tell, it's do-able, but as far as I know, it's never been done. Did I mention plenty of nerve? I'll see about getting an $850 Alpacka pack raft and doing it next summer.
Meanwhile I'm keeping my beach toy handy - it's stable as can be when it's loaded, and it's plenty good enough for most water obstacles.
For those still interested, here are the route details>