First off, great job Ken on making a really nice guide. :) I haven't gotten very far into it yet, myself, but I have it bookmarked as the best looking referrence yet.
I did my AF1, and went after the AF2 last night. I only had time to get the Eldieme part done (boo, school :( ) and I wanted to clarify things a little bit. When I got down into Eldieme, I ran into some confusion, so I hope this helps.. First off, you do -not- have be on RNG as your mainjob or even your subjob to do this quest. I was a 30RDM/9WHM since it's a junk job I'll never play again and didn't mind dying on, and when I got down into Eldieme I got the cutscenes without a problem.
Now first.. There are plenty of entrances to the Necropolis, and Ken said the south one. Just to reitterate, it's the waaay south one, down south of the zone to Rolanberry and near the sea with that little island thing. Don't remember the exact coord now, but that's the one you want.
When you go in, as Ken said you can take every left and you'll get to Titan's gate. BUT, the problem I ran into was that Shiva's gate was down and in the way! I got so confused, wondering if I was in the right spot or not, that I eventually wound up getting aggro and dying--which reminds me, don't forget that the bomb mobs will all aggro to magic also. xD Now, if Shiva's gate is in your way, what you need to do is turn around, take your first left, and go north into that big open room with the Kas and the ghost mobs. On the left (W) side of that room is a gravestone and a Fazer. Ignore the stone, and beyond that is a switch (East Lever or something like that). Now, when this switch is triggered, it opens Shiva's gate but CLOSES Titan's Gate. I had my RDM friend trigger it, Shiva's Gate went up, and on my left (S) in the next room was the Titan's Gate we're looking for. There are two there, though, so make sure you take the S one.
Now, if your friend at the switch hits it again, Shiva's gate will close and Titan's will open and allow you passage to where you need to be. The Gravestone you want is on the N side of the next big open room. :3 And there you have your next cutscene. If your friend is still around, he may have to hit that switch a few times to let you back out the way you came. But, if you know what you're doing, this part of the quest is so painless it's funny. I just hope Oztroja is as easy (doing it tonight).
Thanks again for the good guide!