April 25 to 27: Yellowstone. I have never seen so much snow in Yellowstone before, either in Spring or Fall. The National Park Services called this year's amount of snowfall 'normal'. When I was there, only the north and west part of the park was opened to auto traffic.
April 28 to 29: Little Bighorn Battlefield National Monument, Custer State Park, Wind Cave National Park, Mount Rushmore & Crazy Horse Memorial.
April 30 to May 2: Badlands National Park. Right in the middle of a severe snow storm. The section of Interstate 90 around Rapid City, SD was closed for more than a day.
May 3 to May 4: Left SD and headed home via Glacier National Park. There was still lots of snow on the sides of the interstate highways in SD. St Mary Lake was still frozen solid and the Going-to-the-Sun Highway was closed before the Rising Sun.