I'll just tell you what I did. When I hit 50 I had enough Philo tomes to buy the either the darklight chest piece or the materials for a crafted 2 star chest piece. I chose the chest piece, and after that I started my Relic quest. Did all the requirements for it, went straight to Ifrit then Garuda, then farmed Garuda for the weapon. Soon as that was done, I melded some Vit materia to do Titan (I should point out I'm a healer).

You should honestly be able to do any of the 50 content before Titan that you want. Just get together a few friends who can run everything with you once to explain the mechanics. IMO, everything before Titan is a mechanics thing. It doesn't really matter your gear, if you know all the fights and the mechanics, you'll do great. People telling you that you need full DL to do AK or something is just false. Yea, the healer will have to work a little more, but it just means they won't be falling asleep, or helping to DPS.