This is what I play during Player vs. Environment. Your usually the last guy standing for that fight that didnt go so well, so at least you can keep the team trucking.
Level 20
Expertise- 12
Marksmanship-12
Beastmastery-7
Wilderness Survival-5 (+2 Major Rune) so 7 total
1. Hunter's Shot- damage bonus + if target was moving there now bleeding.
2. Tiger's Fury- for six seconds all your attacks increase 33%. Basically, if your using a shortbow your shooting arrows quicker then Legolas did in Lord of the Rings.
3. Apply Poisen-- nice 24 second duration. Adds poisen damage to all shots.
4. Feral Lunge-- bonus pet damage + if target is moving he is now bleeding.
5. Troll Ungeant-- boost regen +6 for 10 seconds.
6. Charm animal-- must equip or you dont get the pet.
7. Comfort animal-- only way to ressurect the pet.
8. Restore Life-- Yah, my team gets to keep on trucking.
Now let me critique my own build. First off, Im very weary about adding new skills or changing my lineup so Ive had some time to look at this and there are some things that I can change. I dont have any "elite" skills yet so I have to make do with my "normal joe" skills. First off, in Player vs. Environment I cant really remember the last time I hit a target that was moving. Enemy dont move a whole lot after initial contact. So I could probably lose Hunter's Shot in favor of something else that costs 5 with a quick recharge. Penetrating attack maybe? That goes for the pet too. He doesnt hit anything moving either so I will probably swap that to the skill wear your pet either gains health or maims someone. Other then that, its a pretty stable rng/monk build. Almost everything is low cost, plus with a high expertise its even cheaper. No matter how long the fight lasts Ive never run out of energy. Just spam it all.