Yeah, running through the forest doesn't sound like fun... I'd take up mountain biking at that point.
R/C Rally would be cool if it was a combo of dirt and asphalt, elevation changes and a little air time. Offroad RC has kinda turned into Stadium Motocross with its extreme jumps and air time.
I can really see these taking off on small, temporary parking lot tracks. I'm thinking the type of parking lot you see in front of typical hobby shops. Throw down some cones, no track prep and go have fun.