I'm very sorry for not finishing this story. My problem is that I get these great ideas in my head for long stories, but I don't really commit to taking the time to write them. Life keeps moving forward. More movies have been made, and the franchise has evolved over the content of my story. I finished college now, and need to start thinking about my life and career, and would rather spend my free time doing other things besides writing fanfics.
Here I will summarize what happens in the rest of the story, giving some long overdue closure.
Humphrey and the gang all slide down the mountain. They do pretty well, survive a few bumps. It's a truly thrilling experience for all of them. Harrison tries to make it more difficult for them first by having his henchmen push boulders down after them, which they dodge. Next he pushes Pete down after them. Pete grabs and wrestles Humphrey, but Garth helps knock him off, then throws Humphrey a vine, which the latter uses like waterskiing, and gets back on the log. Finally they come to a big jump, and it looks like they won't make it, but they use the blanket as a parachute and make it down safely, and so Milo wins the bet and all the meat.
Winston, Eve, and Tony are really angry at Humphrey and Garth for doing something so reckless and risky and putting themselves and their friends in danger. All the punch and drugs start getting to them though, and they become hungover. They all return to their respective dens for the day, plagued by headaches and nightmares, though Salty's headache immediately vanishes when it's time for his date with Lola.
The next day, everyone awakens and gets ready for the wedding. Humphrey is nervous, still wanting the party to go on, but his friends all convince him that everything will be okay.
At the "alter" rock, Humphrey promises to Kate never to take such big risks again and be more responsible as a husband and father. The cougars arrive, Humphrey making sure the wolves all know they are there on truce.
The story ends with all the cougars and wolves at a moonlight howl reception, much like the end of the first movie.