I always just thumbed it at 400lbs an hour average, then add 600lbs on top of that for reserve. So for a 3 hour flight I'd put on 1800lbs and you're guaranteed to get it there with plenty reserve. Normally cruise at FL240 to FL260, at about 255-260TAS. It has been a while since I flew them regularly though, that's just what is on the top of my head.
They are amazing airplanes, you can do just about anything in them. About the only thing is you can get them aft CG if you really load them down. They are extremely reliable. The legacy models are great. My only beef with them is the generators. The main is capable of powering everything in flight, but if you lose it, the secondary is very limited in amperage output, so load shedding is a must. They fixed that on the NG's by putting two full size generators on them.