I should probably clarify, this is my first time ever running a DnD game and I'm super nervous. I've read the rule books but I don't know how to set things up.
Have some characters ready to interact with the PCs. Preferably funny and interesting ones to help draw players into the setting. Break out the ragmen, the bearded lady, the circus wizard, the elven poachers (what, you expect a naturally chaotic race to abide by its own rules?), the headman of the nearby hamlet constantly beset by elven fuckery, the traveling druid with a massive snake he'd love to show you. Make the exotic beast intelligent and able to speak (as many magical beasts already can, and others could learn to if, say, the elf elder saw fit to Awaken them), and perhaps an entirely reasonable sort at that not necessarily opposed to being put up for show in a circus (if the PCs are able to explain it to a satisfactory degree, that is), provided you could show it a contract with certain guarantees...
Ultimately the adventure is a way to bring people to A) experience and riff on the fun of the characters and events you bring to the table (this includes your monsters, so make sure to give them character moments as well) as well as B) discover and riff on the fun parts of their own characters in the process. Both components are important. Don't be afraid to throw in an in-joke or two to increase player familiarity with the setting.
As for stats and such, don't worry about it that much. Have them ready for the things you'd expect the players to fight (elves, the exotic beast, fun wildlife, the druid's massive snake, local toughs looking to screw the PCs out of their rightful claim, etc.) and maybe write down the salient bits (attacks, damage, HD, HP, saves and attribute bonuses, noteworthy skills and special abilities) on a card for easy lookup.
Maps you can also draw up on the spot on millimeter paper, especially since there doesn't look to be any kind of dungeon component involved. Towns don't actually need maps (neither really does anything else other than immediate battle maps and dungeons), but work out what they look and feel like in advance. Have a broad attitude, look and feel worked out for the forest as well (dark and foreboding? primordially beautiful? colorful yet horribly dangerous? teeming with bizarre invertebrates? unnaturally sterile and park-esque due to elven forestry?), and for elves if you expect they'll be present.
And, y'know, have the dice in place and a spot to roll them.
Other than that, don't feel pressured to work out too much in advance. Invariably the players will have either a mildly different understanding of the setting and the problem at hand from you, so making too much of a railroad can throw you for a loop.