We will be glad to have you back. Not sure when you left. They've added a couple of FPs in "elder content." There are the czerka labs, four dailies plus two flashpoints, Oricron with a bunch of dailies (some can be soloed but a couple require at least two people or top tier gear) with a flashpoint and an op. Then there are the Korriban/Tython FPs which are scailable (you and run at any level over 10). Those last ones seem really easy, at least with the groups I ran.
The Strongholds are only for subscribers come August and some will be expensive. The ones on Dromund Kaas and Coruscant are only 5k to open, but Nar Shaddaa and Tatooine are 2 mil to open. I haven't found any activities tied directly to them aside from picking up mats to purchase/craft decorations.
The guild stuff isn't on the Test Server yet. The guild starship is 50 million. I think that's a goal we could reach but it would require a LOT of grinding by as many people as we could get. The guild Stronghold hasn't been added either, so I don't know any details on that yet. Those are supposed to have content associated with them. If your flagship is orbiting the planet you are on you are supposed to get a buff. Guilds can also fight for domination. As I was moving around Nar Shaddaa, each time I zoned a notice popped up stating that "No guild controls this zone." So, there could be some interesting things there, but as a small guild I doubt we could control a zone for long.