You might think that back in the ice age, there are no mode of transportation as mankind hasn't found how to domesticate an animal. Well, they haven't domesticated an animal yet, but they have cars back in the old days. It is like the modern car of today.
Drive your car as fast as you can till you reach the finish line. Grab as many coins as you can because you can use those coins to purchase some upgrades for your car later. Use the booster to speed up your journey to the ice age. Don't try to have some NOS as there are plenty around just waiting for you to pick up on the road.