I have tried it a few times. It's good if you're new to the game. Otherwise not so much. I found I leveled slower by using it, as it's suggesting to take the longest possible route usually. Basically following roads everytime, when you could take an easy shortcut. Especially if the shortcut involves a bit of fall damage, it's out of question. The "go here" spots don't also update if you take a shortcut, and then the waypoint arrow points to wrong direction. But perhaps it has been updated since then.

Good question. Me personally, when I use a new strat from somebody else, I always read thru the strat, and in the case I really need to level some pet, I then (likely) exclude strats that are mentioning things like “RNG”, “risk”, etc. But: I’m always happy (when using a new strat) when I see some detailed infos, so that I can estimate what is going to happen. But YMMV. 

Simply playing the auction house can be the most lucrative gold making ventures if you have a sizable gold staff and you're not afraid to spend it. Just like a real world stock market, prices of items traded on the Auction House fluctuate daily, creating opportunities to buy low and sell high. Zygor's Gold and Auctions guide finds items that are selling at record lows for you to buy them out!
Felguard: The shocktroopers of the Burning Legion, always seeking out the greatest threat in any particular battlefield. Crazed berserkers, the Burning Legion’s generals have to do little more than trust in their instincts and unleash them upon the battlefields. Demon hunters who bind themselves to the soldiers of the Burning Legion would no doubt become more physically brutal, broad, and capable of withstanding inhuman pain.

Felhound: The felhounds serve the Burning Legion as their devourers of magic, their forerunners, and torturers of spellcasters. An endless desire to devour magic is their greatest trait, especially when paired with their endless appetite for wickedness. Demon hunters who bind themselves to these creatures are no doubt the masters of defeating spellcasters, seeing their spell-weaving enemies as little more than fonts of power to draw from.
2. Your DH needs supplies on a regular basis. They can only carry so much food, clean drink, medical potions and whatever else they want/need at a time. It's pretty realistic that they would need to visit a market every so often, and large faction markets will have the most variety and types of items to choose from. (My DH has been a recluse in the wild for some time, and she is stinky, dirty and has eaten some questionable stuff. This isn't really ideal and a Dalaran doughnut would be pretty flippin nice.)