Look at FAR 135.1 (a) 5

Non-Stop, within 25 NM of airport.

Must Comply with:
135.249
135.251
135.253
135.255
135.353

(Testing for Drugs and Alcohol)

There was some talk about a 500 TT requirement some time ago, but I don't know where that stands.

I did Scenic flights, but the company was 135, and the 172 was a 135 airplane, so it wasn't an issue for me. Some people just go do it, but in todays world, I would be cautious about doing it.

You have the potential to fly a lot of "first timers" and people new to small airplanes. It can be fun/rewarding.

However, you should carefully consider the legal liability of such an operation. If something goes bad beyond your control, and even if you do everything "right" (i.e. forced landing) , you ,and everybody else, could get sued.