I actually did start an adventure tour company several years ago.
We did a lot of outdoor adventure stuff, but no bicycling.
You CAN be successful at it, but you have to find a niche. Decide the type of people you want to work with and target their needs. This will keep it fun for you - so you don't end up escorting a bunch of 9-year-olds or some other group far from your dreams.
The thing I found is that the income can be "OK", but limited. I looked down the road, did some multiplication, estimated realistic goals, and decided that there wasn't enough money for my long-term financial goals.
Maybe your vision is bigger than mine, or maybe your financial goals/needs are different than mine and a tour company can be a real winner for you.
The first step is to get a quote for liability insurance. You can't afford to start without it and it is often too expensive to start with. Liability insurance is a real drag for the small business start-up.
Good luck!
Mike