Instructions
Fly the sabre jet to the army base and parachute to the ground. Defeat the mob and purchase the Russian Digger.
Go east of the fenced-in army base to find a spot to dig. It must be a spot where the gophers are. Use the Russian Digger to dig up gophers.
Whack all the gophers as they come up to play whack-a-mole. The ice cream truck will appear next to the gas station. Purchase it for $30,000.