HI. welcome to awesomeness.

Sadly there is no way to lvl past that first story part without pulling up Duty Finder and going in with a group. If you dps you will have to usualy wait a while to get in. but with the new patch tomorrow there is incentive for others to go back and do older dungeons.So fingers crossed) after tomorrow it will not be so much as a pain as it usually is.

2. Main story has MANY benefits. It unlocks what is pretty much all the main mechanics in the game. A lot of the game is unlocked at certain levels. So you are most def. missign out if you delay the main missions. (ex. chocobo mounts. Retainers.. merketplace.. materia. among others. ) is def. in your best interest to run the main story and then youll have the game unlocked to go nuts with all your other classes

You can level all you want without the main story. but you will be hindered as a lot of the game is blocked behind hitting certain milestones.

The main story is very fun and interesting. Its boring until about lvl 15 though and then never looks back.

Have fun

T. Tinypom