Can you bring firewood with you? Or is there places to purchase firewood?

There are plenty of places that sell firewood accross the street

You can bring firewood for Iowa, not other states. There are stands all over in the area.

And they would prefer you don't bring firewood because it can spread bugs that kill trees

Yes. There is firewood for sale at campground host and on the road in at several places as well as the gas station.

There is a place at the campground to purchase firewood.