This friendly outfit offers four different butt-busting rides on all-terrain vehicles in the surrounding wilderness (two tours are offered year-round, and two are seasonal). Note that you're not allowed to make this kind of cacophony in the national park. Instead, the trips skirt the park's fringes.
There's a ton of add-on cross-experience tours available; you can combine an ATV trip with a zipline experience, a visit to a husky kennel, etc. Visit the website for more details.