Possible Clues:

• Gopher's milieu
• Great grassland area
• Is endlessly nosy about appearance, being plain
• Large tract of grassland in N America
• With 47-Down, Manitoba, Saskatchewan and Alberta
• Partnership secures runs — that's plain!
• — Dog; — oyster
• - - -dog, North American ground-squirrel
• Much of Manitoba
• Couple crossing river that is in open grassland