If they still feature the wine & cheese tasting & quiz, i'd participate in it as it gave us a chance to sample wines we would never have tried coming from the UK. Take a camcorder and enjoy your journey over the glacier national park and the vast dakota plains.
Whatever time of year you do it, you'll love it!
WE were bowled over by Minnesota when we travelled CHI -SEA and the glacier national park going SEA-CHI.
Food and company was great on all three trips.