Just put someone in it and drive it to the exit area. The next time you stop in the wasteland on the way back to the base you will have 2 vehicles. You probably won't use the Scouter ever again. At least you can carry some goodies in it to avoid all your characters being overburdened when you leave Jefferson and before you get back into the Hummer.
Well, you just drive it out. Same as any of the other vehicles. I didn't think that was too hard. Hell, if anything the tank was the hardest to get out.