The best way to have Danger Canyon under control, is to have the tunnels and the ground level/ledges secured. It can be really critical and it can prevent the other team from scoring any flag captures.
Controlling the tunnels: Have 1-2 people in there with a fuel rod and a RL (might be a smart idea) and pistols/snipers to keep them from getting in there. And if they try and go through tunnels with flag, you can easily stop them. The tunnels can be very crucial in CTF on this map, so controlling them is somewhat critical and can help your team win, or prevent the other team from winning, at least.
Controlling the ground: Have a person with a sniper/fuel rod to snipe at any people on the ground or on the slopes that lead to the rocket launchers, or use the fuel rod to take care of any vehicles. Controlling the small structure and stuff in the middle is a good idea and you can take care of any enemy vehicles.
Controlling the sniper ledge: If you can get control of the ledge with the sniper rifle (outside) with the teleporter and OS, then you can make things for the enemies on the ledge across very difficult. Keep two pistolers/snipers up there.