I am assuming the state fairgrounds. Good facilities. Depending on how many head, there should be plenty of room.
I would bring a generator just in case. I know there are issues at state fair time with breakers being blown. The barns are generally the coolest place on the fairgrounds! Good ventilation up top and all four sides, so it stays decent inside.
I have never seen a port a cool there, so doubt it. Especially since they use a water source. Fans should provide enough cooling.
Tie outs are about 400-500 yards from barn. They are usually in good shape at summer shows, but during the state fair they get pretty nasty toward the end. There is no shade at tie outs.
The area around fairgrounds is good. Residential on two sides, HUGE camp ground to the east and residential/gas stations, fast food to the west.
If you are going, you need to eat at: Jethro's (BBQ, Smokehouse) it is about 5 miles away in Altoona, but fantastic food at a reasonable price. Big steer is a steak house that is good, but a bit expensive, also in Altoona. Several other places that escape me right now, but will try and remember them.
Sight seeing? Not much that isn't typical of any other town.... Science Center is pretty fun, it has an IMAXX theatre and lots of hands on activities for kids and adults that like to act like kids (me included!). Adventureland is your typical miniature "worlds of fun".
Des Moines is pretty easy to get around in. When I am in town, I usually stay in Altoona, it is about a 15 minute drive, easy roads, and rooms at the best western are nice and affordable. I would NOT recommend staying at the hotel right next to the fairgrounds.
You have to go to Hawkeye in Adel, which is about 20 miles west and Nichols Genetics which is about 25 miles north. Both are super bull stud places, which generally welcome visitors with open arms!
Hope you enjoy your visit and have a successful trip to Iowa.