To be honest, with the exception of some primal fights and some of the necessary story dungeons, I've never really used Duty Finder... until CT, and that was only from a week ago. I've done maybe... 1? 4-man lv50 dungeon ever, and that was AK for relic (and with friends). CT is definitely forgiving and if you can afford it, you really don't even need to bother running anything prior to that if you can buy gear/materia. I try to avoid PUGs as much as possible, which is why it's best to find yourself some friends to do things with once in a while, but my own experience with PUGs hasn't been TOO bad. Yeah, people bicker about the dumbest things sometimes, but I'm actually seeing people be a little nice once in a while. Folks actually greet each other!

My personal route was to just craft the ilvl70 gear, meld it (though not entirely necessary), then do whatever. You can easily gain enough ilvl to hit CT by doing a bit of that, and CT is of least consequence when it comes to ilvl... you just might want to learn about the fights beforehand lol. Where gear cannot make up for lack of knowledge, fight mechanics are exponentially less forgiving. CT will also net you some Myth/Soldier tomes as well, so that'll at least help in accessories and the like.