Here's a new kind of guide. I call it Phigerstance udyr because its mixing both tiger and phoenix (obviously), and it's really strong. You're still that tanky Udyr but with lots of damage and i'm 100% sure you can solo Baron when ur fully built.
If you wanna see the guide with only tiger stance udyr instead of the mix, you should go visit sp4zie. He made a guide with this: http://www.youtube.com/watch?v=JZB1JyvtEAc

These runes benefits udyr's agressive playstyle and i kind of stole them from Diamondprox (Gambit gaming) at the LCS. The runes is used to do some nice deeps and some nice early game damage.

These masteries... I stole them from Diamondprox too, because they're so good for sustain and so on. The buff duration, and the offensive stats in the offensive tree, will really help him doing some nice damage, and if you build correctly you should be tanky with lots of hp, resistances, damage and nobody can escape you.

Your items will be a mix of alot of damage, Movement speed, tankyness, slows and resistances.
The iceborn gauntlet, blade of the ruined king and ur ghost will make you unstopable. No one can escape you, not to mention the boots.

I think ur route is actually free. But make sure you don't get invaded. For example: They have an enemy Lee sin. He usually starts red. Then you do your blue, because he cant get to that before you. If you really know what ur doing on junglers, then start blue, make your support ward their blue, and stand by, with smite on the enemy blue, for a smite steal. That way you actually have control of 3 buff/buff timers.
Your key to agressive jungling is:
1. Know the timers on the buffs on BOTH sides.
2. Let your team know what ur doing. "yo im going for their red. Mid come help me"
3. Remember the enemy cooldowns and summoner spell cooldowns. For example: Flash. Go top, force flash, jungle a camp, go top again.
4. Always do something EXTRA. For example: You got a perfect gank of at bot. Go take their tower. If you manage to get their tower, go take drake. If you manage to get the drake, try a gank mid. Always do something extra.