First time around I got lost on Dantooine most times, lol. Yeah Dantooine was a good planet extremely large. Dantooine and Taris where pure quality planets, for some reason they seemed the largest, probabally because you had to work towards goals set to you, and then to ultimately get to the goal other side quests where unlocked and you first had to unlock them.
In the remaining planets you basically had to find the Star Map and pretty much go away, but there was 1 main thing that was a problem that you had to solve. Kashyyyk was the Slaver problems and Zalbaars brother, Manaan was the whole missions for the Republic, Tatooine was like the Tusken Raider problem.