Finding a cosmic world destroying needle in a hay stack made entirely of fire.

[MonkeySage]

So my party (we're all level 12, and my npc apprentice is level 10) will be venturing to the Plane of Fire next week, starting at the City of Brass. My apprentice has two Plane Shifts (one for the return trip) and 5 Resist Energies prepared, as a level 10 Cleric of Desna (Travel and Luck Domains). As a sorcerer, I can cast resist energy on myself no problem, so the rest are for the rest of the party.

Problem is, the spell as cast by my apprentice will only last for 100 minutes, and we need to find the proverbial needle in a hay stack within that time. A bunch of druids scrying for the object were only able to tell us that the object we need to find and destroy is on this plane, not specifically were it is.

The object is tied to planar rifts, simultaneously plane shifting and teleporting in place at all times. We left a copy of it with the druids, and it's doing the same exact thing. The Plate we left with the druids can be scratched and dented, but we can't destroy it by physical efforts, and we don't have the power to remove the magic from it. But that's all something we'll need to worry about after finding it in the first place.

So, how else can we prepare for this trip?

[Firebug]

Planar Adaption (http://aonprd.com/SpellDisplay.aspx?ItemName=Planar%20Adaptation) would extend your time frame to hour per level instead of 10 minutes and your cleric should be able to cast it multiple times.
Flight(overland or otherwise), for when you don't want to walk across the lake of lava.
Locate Object, but you have to be within a long range and had to have seen the unique item before (or be looking for a more common item).

[MonkeySage]

Would a copy of the object work? Our druid friends were able to scry on the one in the plane of fire using the one we had.

[Malroth]

Before traveling have one of your Cleric friend cast divination to find out the name of the specific location where the plate is then have your druids cast find the path targeting that location.

[MonkeySage]

Now, it is risky and I'd feel bad asking the druids for anything else after the last time they scryed on the plate- it resisted their efforts and caused all but one druid to lose consciousness. They all suffered injuries from just scrying on it.