Montana game biologists are forecasting Northern (above the Highline) and Eastern Montana ( Plentywood area) Pheasant numbers to be below average by as much as 50% this year, due to large winter snow pack, cold spring, and spring flooding. South Central Montana (Great Falls, Lewistown) numbers will be fair to good, near 10 year averages. Long drive from Iowa.
Southeast Montana, along the South Dakota border (Miles City) will have average numbers of Sharptails and below average Pheasant hatches.
South Dakota had less snow than usual and no flooding and is forecasting Pheasant numbers the same as last 5 years.
My experience with hunting Eastern Montana, and the Western Dakotas is that in most years hunting pressure is very low on Montana Block Management land and bird numbers are very good (except for this year). There is very little public land in Eastern Montana and most of it is heavily hunted. Hunting public land in South Dakota early in the season is very productive but extremely crowded. Most of the best hunting in the Dakotas is on private land with per gun fees. Later in the season you'll encounter few other hunters, good bird numbers but birds will be widely dispersed and much spookier than early season.
Unfortunately, South Dakota private land is your best bet this year for a successful Pheasant Hunt, but most pay per gun operations limit numbers of hunters and can almost guarantee a successful hunt with no other hunters in the field. Many of them can also accommodate your camper.
I'm headed to Missouri and Kansas for Quail this year, but I will swing through South Dakota in Mid to late November, weather permitting, hoping for light snow on the ground which will tend to bunch the birds.
I'd contact the game biologists/managers in each of the regional Fish and Game offices in areas you like to hunt and get current outlooks for Pheasant. I've alway found them to be very helpful.