Hey all, just wanted to chime in as one of the founders/developers of http://ridewithgps.com. You can see we are heavily marketing towards cyclists, however our roots are in motorcycles. The site first started as a way for Zack and I to map our motorcycle rides, well before we started recreationally bicycling. Turns out bicyclists are a monetizable, paying audience so we pivoted towards them (as we became cyclists ourselves).
With that being said, 3/4 employees are avid dual sport riders, so we will always have features that are handy for on/off road riding. We are planning on doing the OBDR this summer as a work expense and are developing a few features to make planning a multi-day ride a bit easier. Here's what we have so far:
http://ridewithgps.com/events/Oregon-Backcountry-Discovery-Route-OBDR