OMG, you're a UA 2P, AA PLT and you've never been in a puddle jumper?
Are you in for an experience. ^ The FA's are really hard to find, and the lav is also so small you will have a hard time finding it.

The food will be worse than anything you ever got served on DL. The FAM sits in the only FC seat so no upgrades for you, Plat.

With 310 horsepower, get your legs in shape--those pedals at each pax seat are the BOTMS: Boost Over The Mountain System. With an empty weight of 2400 pounds, this large looking pile of metal weighs half as much as your SUV!
Seriously, if you like to fly you will love the experience. Ask to sit in seat 1B. This thing has six seats. One for the pilot leaves 5 for pax. Seating in a Cessna is like sitting in an old VW Beetle. Seat 1B is the right front and has the best view and comes complete with an operating set of flight controls! And the most leg room. ^ Ask if you can fly the plane for a few seconds. Don't try that on UA unless you want to win a free trip to Gitmo.
The smoothness or bumpiness of the flight entirely depends on the weather that day. Small planes can be glass smooth or dirt road bumpy. Don't eat or drink a lot for several hours before the flight, if it happens to be bumpy an empty stomach handles it better. A recent big meal bouncing up and down is less fun in a small plane than in a big jet.
Don't forget the Trip Report when you get back!