You could just go ahead with the story to level the SMN up. Otherwise, if you're interested in gathering and crafting then just go ahead and do that.

You're not missing anything if you don't have a capped job. The game doesn't take away things, they just put in more and more of stuff and they're all staying. So you can take your time to do what you want and when you want to do something else, there's always something else to do.