its even possible to reach 75 soloing?
It's possible to reach 75, hell 90, in a single day of partying once you hit 30, but doing it that way isn't really recommended.
The level cap is now 90; it is supposed to be 99 eventually. Abyssea is the last three mini expansions. Each expansion buys you three zones. Abyssea is the new (much faster) way to exp/merit. Abyssea, revolves around getting monsters to drop the right chests. Some chests drop time extensions (the Time limit inside is initially 30-120mintues, but it can be extended infinitely, as far as I know) Some drop exp, cruor (the "currency" of abyssea, similar to ISP/CP/AN), temp items, or normal items. Others give you lights, which depending on the color can effect anything to chest drop rate to the amount of exp you get.
Most of the new gear, including AF3 and new weapons, come from NMs or doing trials in abyssea. On Asura, at least, there are usually shout groups forming in Port Jeuno, or it is easy to make your own shout group(PJ is the new WG, because the npcs that teleport you to abyssea are there). In addition to gear, hunt down abyssites and atmas, which are enhancements that make you much, much stronger inside aybssea.
To get started, talk to Joachim in PJ. He's standing right next to the top of one of the stairwells. Get a traverser's stone, and head to a maw. (each stone initially gives you 30 minutes, and Joachim gets a new one every 20 hours initially iirc. He can store several at a time, but will only let you hold 3 at a time. The limit sounds annoying at first, but once you get into the swing of things, you have plenty of time to spare.)
There's a lot more I could say but I see this turning into a wall of text quickly. Here is the wiki page if you want to know more. http://wiki.ffxiclopedia.org/wiki/Abyssea Edited, Apr 1st 2011 10:37am by RizzoRazzle