So the scout is one of the more active roles, you are always on the move, typically running for power while your teammates mop up the last few enemies each round. The skills you will want is, of course, common green (Deposit Bonus, Health Boost), Health Regeneration, and Pickup Radius. The 5th skill is the only one skill I feel you could trade out for something of your choosing, all the other skills are practically a must. I like a rare blue (Dodge) since you are running around a lot or a rare blue (Team Revive), or the one that makes you run faster, those are all good choices.
Raven Down, Checkout, and Harbor are all fun easy Levels for the Scout typically. If you have any questions are can't get this achievement yourself then hit me up on here or on Xbox Live. There is no One Ultimate guide for these classes so have fun with it :)