If you're in your 60's and you're attempting to access Henne Mines.Ex, then I'm guessing your party will be wiped out quickly, unless you flee all the way to the Pithead Junction and do the set gambits I wrote a few posts previous to this. If you're looking for easy leveling around your level, then I would advise heading off to Giruvegan (Kill off Behemoths and the flying gargoyles) or go to Subterra in Pharos, but you definitely need to have the appropriate gambits to even challenge the first hurdle of monsters who will enclose upon you.

Simply have your usual buffs and set these for attack:

Attack: Foe- Nearest Visible (For leader)
Attack : Party Leader Target (For two subordinates)