See if you can find out if it's a steel or aluminum frame. The 6061 is likely an aluminum frame, which would stand up to the elements better, and is lighter and favored by more serious riders. If it's been outside for 2 years and exposed to rain/snow/etc. it's likely the components won't be performing their best and may have to be replaced, depending on how extensive the rust is, and how well the owner treated the bike. But if you're more of a casual rider it will be a lot cheaper (and a lot less painful) for you to buy a brand new bike from Target or Sports Authority, many of which are in the $100-$200 range.
