Hi! I started playing again a few months ago (was also a 75 SAM) and was at the same point as you, nothing past WotG. These are a few things I can think of, so I hope they help! Others can probably point out where I'm wrong. Lots of the new end game stuff is still a bit of a mystery to me.
Related to Trusts, I would also make sure to sign up for a Unity. This way you can start collecting accolades for some level 99 equipment. I've not actually done any yet so I don't know if it's any good, but it doesn't take long to sign up and you get a buffed up Trust (a lot of people pick Apururu for healing).
Related to that, remember to use your Records of Eminence to collect a currency called Sparks and get extra exp. Sparks can buy you a pretty decent set of iLevel 117 gear to help while you work on getting better equipment (or just get you through the story that was in the base game, which is what I'm using it for). You can also use Sparks to buy items that are needed to reforge armour to bring AF and other stuff up to iLevel119, that might be a goal for later though.
Rhapsodies of Vana'diel is a must! The first chapter is pretty easy up until the last boss in the mission which you'll probably need someone level 99 to help out with. Depending on your progress in the game's story you could start the second chapter, but I don't know enough about it to give any advice. The Rhapsodies key items give you a permanent boost to your exp (there are 6 so far, each gives +30%), as well as other bonuses like a 90% reduction in teleport costs, the ability to summon more than three trusts at any one time, etc. This also gives you access to a new area which is amazing for getting limit points and experience around level 99.
Regarding getting money and farming, I've not needed to do this to get gear besides one item once I hit 99. As far as I know, people tend to solo Dynamis and other events to make money now. For money to 'get by', which is what I've been using, you can get from Sparks. You can buy a shield in the 70-98 category of gear called Acheron's Shield which vendors for around 26,500-28,000 gil depending on fame.
Repeat Login Campaigns and other campaigns that're running can be found on the playonline site which is always worth checking. Log in points in particular can get you a bunch of good stuff: trust ciphers, items for quests/limit breaks, seals. At the moment one of the rewards is a Kupon I-Seal or something, which a friend of mine (I'm clueless about) says are really good as they'd allow you to reforge Empyrean Armour, which I think is from Abyssea. I'm sure someone could tell you more about it than me if you were interested.
Speaking of Abyssea, even if you don't have the expansion, I would see if you can get the bonus items from the Abyssea Campaign since they should open up a lot of the area to you if you ever decide to upgrade to the add-ons and Seekers of Adoulin expansion pack. I think it's on sale at the moment (the ultimate seekers edition) but I've seen it on Steam for £2.50.
Finally (Sorry for rambling on!) regarding your question about places to level. Around level 75 I still found things like Heraldic Imps in Caedarva Mire good exp, as long as you have four trusts from Rhapsodies (you probably want Ayame and Apururu UC at least, if not Kupipi is fine, plus another DD and a tank. Trion is best. But Ayame is a must for skillchaining). Another good camp for 80+ is Slough Skua in F-9 Caedarva Mire. Alternatively, people seem to like Quicksand Caves, Kuftal Tunnel, Labyrinth of Onzozo (I fought Torama and Manticores there using a Grounds of Valor tome that gave extra exp until about 75). Remember to check for Survival Guide teleports, which appear on your map as little books, as well as use RoE under your quests and GoV/FoV in the zone. They also added a lot of level 80+ enemies to old areas in the game. You could try Fetor Bats, Thorn Bats and Fuglio's in Outer Horutoro Ruins for 80-85. Another one I liked from 88 to ~95 was Balayangs in Fei'Yin, but you could probably do these up to level 99 if you don't have Seeker's of Adoulin. If you get Seekers of Adoulin I would recommend the Mandragoras in Ceziak Battlegrounds after unlocking Ionis, which is the Adoulin version of signet/sanction, by progression the first couple of cutscene missions. After you reach level 99 and have your Sparks gear, Eschan Tabachiniks/Opo-opos/Puks/etc in Esha-Zi'Tah, unlocked through Rhapsodies, are best for getting a ton of merit points, job capacity points, and sparks, especially when the limited time challenge Gain Exp is in effect.
Hope that's not too much to have scared you off! I hope you enjoy your time back in the game! I went back in pessimistic, but have had loads of fun!