I know the feeling. I moved on to Corelia before I finished Tantooine, and I will likely step it up a bit to Dantooine next. I like to explore, that is why I became a ranger in the first place.
As to peoplel, that depends what city you hang out in as to whether or not you can find people to group with. Chilastra really isn't that barran, there are just 8 of those worlds. If you hang out in Mos Eisley you should find a group no problem. If you hang out in Coronet you should crash 4 or 5 times no problem.
Coronet is definently the most populated city on chilastra. You can find anything you want there.At higher levels, you may even want to go there to form a group to go to say Dathomir, since it is a straight shot to the planet of whitches as well as every other planet except Loki and Rori.
And I don't know about server downs, the only time it has ever happened to me is when I leave my computer on during the day. Maybe you re just unlucky.