Look at Outward Bound, and any of the bazillion outdoor guiding places. There's a lot more of this going on than you'd think.

Things you'll need to do - look at the classes offered by NOLS. You can easily spend thousands and thousands of dollars on outdoor certifications. Upwards of 15-20k, easy. Any time you take someone into the national parks there are additional fees - you need to get set up with them, permitting can cost you. Same with any other jurisdiction including national forests.

If you start your own business doing this sort of thing, and intend to provide transport as well, expect to front 50-100,000 bucks the first year - insurance for driving a van full of customers to a trailhead runs upwards of $15,000 annually, not counting the cost of the van, fuel, and your commercial driver's license.

If you do more than hike and backpack - like mountaineering, climbing, fishing, expert photographer, etc - you will be more marketable.

Yes, I've looked at this myself. Yes, it's not what I'm pursuing, because frankly, it would cost more than I would be making... And, I organize outings for people in my hiking group all the time. Frankly, there's no predicting what people will decide to do at any time and the experiences I've had make me leery of doing anything in the wilderness with a commercial/nonprofit.