Up next after this should be the lvl 95-100 Atlantica guide. There is a steep grind at those levels compared to other ones.

Level 59-67 (Hanging Gardens of Babylon):

For the first time in a while, you will encounter some easy enemies with one or two exceptions. Almost any enemies here are good for farming with the exception of the Keysha enemies. I personally recommend the Slave mobs. They're relatively weak but still give decent experience and drops. Most of the enemies here are fairly weak and worth training on. The first miniboss here is the Iron Doll Reaper and it only appears in the entrance area. It attacks like an axe would so that means your entire row could be dead in a few hits so keep that in mind. The second one here is like a giant Lionman. They tend to drop a Secret Material Chest. Something that lets you pick from either Growth Vials or Mandragora. A lot of people are willing to pay high for Mandragora, but Growth Vials are much more useful to you in the long run. The Prophet quest does not begin until atlantica gold level 70 so in order to obtain it you will need to revisit here later. The boss here (Tiamat) is fairly tough as well. I recommend you get Osiris gear or Judgment scrolls before coming back for a serious fight with it. It can attack an entire column and has a powerful area skill as well.

At level 63 you can do the Princess quest. Its fairly simple and very easy compared to the Exorcist one. A group of 2 will do nicely and the enemies have low HP and high damage. The Crazy Minotaurs are a nice place to train and farm. If you plan to get an Inventor, you must do the Princess quest and level her up to 50 first.

Level 67-75 (Valley of Kings):

If you have not partied up to this point, you will start having trouble. Enemies here are aggressive sometimes and mob very frequently. The Mummies on the first floor are very troublesome. The Mummy Magician use a super powerful poison that will kill fairly quickly. The best mobs to grind on are the Anubis on the second floor. The magic types have a high damage if they use the skill, but they can be Mana Sealed and die quickly. The Sphinx on the third floor have Marble weak against skills and the other weak against physical. You can deal with that but its more annoying than just dealing with the Anubis types. There are multiple mini bosses in the Valley of Kings. The first floor has a large dog but I don't remember the atlantica gold name. It only hits 1 target but deals insane damage. The second floor and on has the Silent Cannoneer. If you skill it it will die fast but regular attacks are just as good. It hits 5 targets but is very weak. Both have a good chance of dropping Osiris boxes that you should stock up on if you can. Your goal should be to make +3 Osiris gear for all your mercenaries. They continue to drop in the next dungeon, but the enemies there are more annoying. The boss here is King Khufu. The difference between the previous boss (Tiamat) and King Khufu is how they attack. King Khufu attacks a row instead of a column and is a bit stronger. Other than that not much else is different. If it is too difficult, go to the next dungeon the Sunken Machine Shrine to train and return after.