Dunno depnds what kind of dragon he is .
Maybe it's one of those low-cost dragon jobs where all you have to do is sit on top of old treasure and hope nobody bigger than you appears.
That’s most of space for ya. Insanely void of very much. Imagine being stuck there, and also being immortal. The distances you have to travel before you get anywhere (assuming you could somehow move a little bit via some means of propulsion.)
I was thinking another planet first.. like Saturn or Neptune, but maybe out in intergalactic space or some world in another galaxy too . You can pretend to go as fast as you can imagine (even faster than light).