In the short-term you can join parties in Bos(tab) Obliutte that do GOV Page 4 on Leeches on the lower map of the dungeon. Skillups for 75+ will be pretty non-existent. This will be much faster than soloing.
If you do want to solo, you can still do puddings in Mount Z until 77 or 78 (bring bands for 77 and 78 to help those levels along). These will keep your skills high (you can cap into the low 80's on them).
To get into Abyssea, make sure you start the quest to build up stones so that you can get access to the zones. Shouts for atma parties are rather rare, so see if you can get a linkshell that helps new/returning players. BLM specific atma include Minikin Monstrosity (50 INT, 10/tic refresh, -Enmity - NM Durinn), Baying Moon (30 MAB - NM Lugarhoo), Ultimate (50 MAB, some MACC, in return for slightly lowered MP - Ultima Title), Beyond (Ice Atk +, Light Atk +, 30 MAB - VNM Konstat Highlands T3).
If you have a ton of stones built up, you can try to scout to see if anyone is killing these NM's and ask to join just for the Atma. There are other Atma that you can pick up in the meantime that are slightly less powerful or offer different benefits that might be useful for a BLM. Someone else may be able to provide a link to a full list. Otherwise a google search should turn a list up.
The Abyssea zones that frequently have parties are La Theine and Altepa. La Theine is on worms or sometimes frogs, both camps are on the eastern edge of the map. Altepa parties are on dolls and in the Southwest corner of the map.