The first side missions "$" you come across are really simple"Can you get from Camp X to Camp Y in under 2 minutes?" You can pass these easily with lots of extra time, BUT DON'T. These missions do not disappear when completed. They allow you compete against your previous time for the same $5000 prize. So if you let the clock run till its been 1:55 before completing and then come back and do it in 1:50 then 1:45 you will net yourself alot more money.This train of thought works for other missions too. There is a side mission where you push a barrel over 50m, but you can keep trying so ideally you would push it 50, 51,52,53,54 to the limit.