RVer needs some advice on a seasonal campground

I got an email from an RVer who needs our help.

She currently lives in the Gulf Shores and is looking to visit family and friends in Illinois for a 3-to-4 month extended stay this summer.

She'd like to find a campground offering seasonal sites for about $500 a month. She'd prefer the campground be in Illinois or Michigan, but also said Iowa and Indiana are options, too.

She realizes finding a seasonal at that price might be difficult, but she's hoping we're up to the challenge.

Any ideas?

(Reply in the Comments section with any suggestions)