I guess the thing is that if you are seriously "city locked" and can't escape those dreaded lights a mobile situation could be a viable solution. Doesn't cost as much as a dark sky property (
I know because I've just done that ) and if you still have to work you can have the best of both worlds. A second hand caravan wouldn't be too much ( doesn't have to be flash ) and the modifications as Houghy says are possible if you're handy, you just have to have the will and the time to remodel it.
Then you have to make friends with someone in the bush so you can park it at their place