The walk from Stratosphere to Tropicana is 2.6 miles so you could probably walk from Mandalay to Klondike. I just don't remember exactly how far away it is since I was driving. It is on the east side of the strip south of Mandalay.

If you are just looking for cheap gambling don't forget my favorite place - Slots A Fun. They have $1 and $3 BJ and I believe $.50 Roulette and $1-$3 craps. You even see there cocktail waitress frequently. They even have no smoking tables.