I haven't, but my brother used to live up by Sheldon. It depends on where in NW Iowa you are going. A lot of it is as flat as my kitchen table and no cover anywhere. I remember when I went to visit him passing the Hillview Farm. D@#%] If I know where the hill was, but I guess you could see it from there. Closer to the river it gets so steep if you trip, you would roll down the hill, and they are fairly tall!
I would advise you to get your boots broke in well as it will be a lot of walking. According to the DNR Roadside survey, most of NW Iowa looks good to excellent for pheasant and pretty good for gray partridge. The link is at:
http://www.iowadnr.com/wildlife/files/upmaps.html
Don't know what else to tell you but good luck!