I have not been on the OC&E Woods Line State Trail, but I found some people who have. Most helpful was Zach Gilmour at Hutch’s Bicycles in Klamath Falls (541-850-2453). He has ridden most of the trail and here is what he says:
Best type of bicycle to use: “It’s soft gravel for nearly all of it (the last seven or eight miles of it closest to Klamath Falls are paved). For what I’ve ridden on the unpaved portion of that trail, a wide but low knob 29’er tire would do the trick perfectly.”
Water availability (streams, creeks, etc.): “As far as water stops goes, it’s pretty bleak out there for any kind of civilized water. The trail runs very close to and crosses Sprague River and Five Mile creek at several locations. You would be best off bringing water filtration.”
Location of the trailhead in the Sycan Marsh: “For the location of the Sycan Marsh trailhead I actually did a bit of digging around. Nobody I knew has ever been out there so I called the park ranger responsible for that area. The closest access to Sycan Marsh is from Horse Glade trailhead. Apparently there is a gap in the trail that was put in to deter motorized vehicles from driving on it between those two locations (there are endangered species in the marsh). To his knowledge it should be accessible to bikes and hikers still. You should be able to access the Horse Glade trailhead off of Ivory Pine road and turning on road 27″
and so on: “We get people from time to time asking about this section of trail but I have yet to hear of anybody that has traveled it. The park ranger even admitted a degree of ignorance to specifics of things out there. It seems to be a very remote area. If you do make the trip, I would really like to hear about it!” I do have first-hand knowledge of many of the dirt roads and ATV trails in the land just south west of Sprague River. If travels bring you through there I should probably be more helpful.“
I also found this journal on crazyguyonabike.com. It has some good info, but is a little dated… 2008. I hope this helps you plan your trip. I can’t say enough about how helpful the folks were at Hutch’s with my questions and they can also help you if you have more specific questions or need supplies before your ride.