That's why popular businesses for money laundering are car washes and nail salons. They're mostly cash based, and have very little in the way of inventory, so it's easy inflate your sales.
But a car wash uses water and a nail salon hires workers. Shouldn't take long to check that those numbers don't add up with what was sold at the end of a month.
I'd think a video game arcade, especially one with laser tag, would be the best option.
Especially if you stick with quarters instead of using game cards like most modern arcades. Since quarters would be recycled anyways (Taken from the games and restocked into the quarter machine), it makes it easy to just deposit the cash you want to launder as if it had been fed into the quarter machine.