I managed to get Stonecore done last night. It was a little tricky, but nothing too bad.
My group is 4x ele shamans and 1x Druid tank. My guys were 82, and they barely met the requirement to random Q for it. I basically used any of the gear I got from questing/instances to upgrade my characters to meet the requirement.
The first worm was really easy, just tank, and then keep moving when he goes underground. Stop and heal your group to full when possible.
The second dragon boss was very easy, just tank him facing away from your group. Strafe your group out of the fire zones. When he goes up in the air, all follow each other and avoid the rocks that fall. Pick him up when he lands, and reposition your alts.
The third boss was the rock boss. He was easy. Just avoid the ground slam by running your tank out, and keep your dps at range.
The last boss was a bitch. The adds were a killer. What I ended up doing was keeping all my guys together when she went up in the air, and then tons of adds came (Too many to pick with my tank). So, I used a earth bind totem, 4 magma's and then fire nova'd them. That was the trick! (Thanks to Kensin/Zulian from KJ for letting me know about this). Once I figured that out, it was much, much easier and I didn't get killed by the adds. You do need to keep moving quit a bit and spam follow because your guys get thrown around a bunch. There are void zones as well, and rocks fall at certain points. Stop and heal when you can. I think I probably wiped 8-10 times before I figured out the earthbind/maga/fire nova strat and then it worked great.