So, I just wrapped up the mines, and Immaculate Trial Dungeon, I went to continue, and then realized I'm about 30,000 XP shy of level 14.

I've done everything I've found (Hiberheim, all random encounters), so I've sorta hit a wall. Anyone know what to do?

If you have cleared pretty much everything in Luculla Forest (you may want to wait a bit for the northern lava area) and Hiberheim, there are bridges to the Phantom Forest south of the Sacred Stone waypoint and past the trolls not far from the goblin village waypoint.