Skarner is one of the best junglers right now in the 5.7 meta he works very well as a tank and AP/AD off-tank. One reason I picked up Skarner was I wanted to play an underplayed champion and be ahead of the game. With Skarner you will be able to win games and usually get the opposing team to surrender within 30 minutes. Many frown upon Skarner due to the fact that he wasn't very good in the older jungle but now with Cinderhulk as well as the stalker-blade combo he scales really well as well as ganks and team fights really well. He has great early game clear and sustain and great lock-down and team fight in the late game. Skarner is definitely a jungler that will be seen in the next patches.

These runes set you up with great early clear and early damage. They also give you enough sustain so that you can stay in the game and not falloff.

I go 9/21/0 so that I have enough defense to clear camps and do early games with ease. Also since I run AD/Tank runes the defensive runes gives you the edge to stay in the jungle and farm and give ganks as well while having the health and defenses to do both.

Cinderhulk is great because of how much Aoe damage you will have with your Q as well as the Cinderhulk Aoe. Trinity force gives you the sheen procs as well as the movement speed needed to successfully pull off ganks and engage/disengage. Swiftness Boots for the cc reduction and movement speed. Spirit Visage for the MR, health, and sustain. Iceborn Gauntlets for the slow as well as the mana the armor and especially the sheen procs. Lastly Warmogs for the sustain and lots of extra health.

Q>W>R>E

The Q is good aoe
The W is great for ganks and engage/disengage
The E for slowing during ganks or while running from enemies
The R for great the cc and the pick off in team fights and since you are so tanky you can just grab their carries and run

Overall Skarner is a great jungler right now with the new S5 jungle and new cinderhulk/stalkerblade adds into the game. He is mobile, tanky, has lots of sustain, and does a lot of damage. Those are all the things needed in an S5 jungler to succeed in this season.

Pros
Tanky
Mobile
Does lots of damage
High health sustain
Cons
Mana problems
Needs damage on team to confirm kills

Jungle path
Gromp
Blue
Wolves
Raptors
Red
Kronks
Crab
Gank mid