I emailed this dude about parking http://www.bnbbengalbus.com/
here is his response
You guys sound just like us, and are welcome to tailgate with the BNB Bus in
Parking lot "E" between the river and the stadium. However, the Bengals control
the parking lots and you would need to contact them to get into our lot. Our lot is
usually where all the busses and Rv's park. I don't believe you can get in this lot the
night before but if you ask them they might allow it.
If you can't, there is a Holiday Inn just west of downtown and an office complex that you
could probably park in on West 8th St. in Queensgate! Let me know where and when you guys
get in, so we can hook up!