What laws apply as I want to do it a low key as possible???
You might start your quest by investigating any city and/or county ordinances for establishing such facilities.
You'll need to know if city or county licensing is required.
You'll also need to know about health and safety laws that must be obeyed.
You'll need to understand and adhere to local zoning regulations, too.
You'll also have to determine if state licensing is required, and what state laws apply in regard to the activities involved.
If children are to use the facility, you'll need to know what (if any) background checks must be passed and by whom.
You might wish to retain the services of a local attorney, before you become too deeply entangled in any business enterprise.
Your state is one of the most burdensome upon businesses, so make sure you know what you face before you begin.
That means you should retain professional service before embarking too far along on this journey.
A respected insurance agent or broker might be able to offer you insights about what insurance limits you should carry, as well as assistance on regulatory matters.