Trouble with the exercise is that Saxony (and all other German minors with the exception of Bavaria) are two weak and surrounded by GP's to really do anything. Saxony being landlocked makes things even worse.
The only way to make headway is to game the system by using a much bigger ally to conquer land for you which is incredibly gamey.
Sure you can try to cling onto GP status but by the time the 1870's come, Japans gonna westernise, Italy's gonna unify etc, and prestige alone, ain't gonna cut it.
Looking at Saxony specifically the most fun I see that can be had would be to play Prussia/Austria off on each other, its historical and if you're lucky you might be able to grab Silesia or Bohemia.
After that though, I don't really know, you'll still be landlocked, you won't have enough power to unify Germany until 1900 and by that you'll be so far behind theres no point.
IMO Italian states are much more fun than German states because theres a much more equal playing field.