Needed:
Cartography
Lockpicking (for the two highest level maps, or all maps if you don't have magery; GM magery works to unlock the first 3)
Suggested:
Remove Trap (you use RT to disarm the chest traps, which are based on a timer. You can do it by using 0 RT skill (using the skill is actually required to start the process, even if you are at 0), BUT will have the maximum length disarm time and will be guaranteed a monster spawn every check - a monster that has no loot and can't be tamed, unlike the initial chest spawn and spawn after opened.). High RT will shorten the chest timer for trap spawn, to where at GM RT, level 1-3 chests will have only one or no spawn, depending on how quickly you kill the initial chest spawn and start the RT process.
Everything Else:
Whatever you want to put the other 420 (520 if you go the 0 RT route) points into (plus equipment for higher skills)
For a Mystic, this would be Mysticism, Focus, and 2 other skills.
A tamer would be taming, lore, magery, and probably vet.
There's other possibilities to play with. I have a melee TH but he has trouble on Hoard/Trove if there is more than one dragon (Ancient Wyrm, Greater, or Frost) in the initial spawn.