As for leveling up. Have you tried using your hunting log? It give really good exp for killing just a few mobs. Doing fates in a party give more exp then solo as well.

You can start a craft at any level. But I recommend you wait until level 50. By then you will have a good about gil saved up. That's if you take the allagan pieces instead of gear you don't need. You can also take up a gathering of some sort (mining, botanist).

There is endgame content. Dungeons, primes, raids, etc.