Cubdrummer,
Sounds like $600 is more than fair. The accessories that you are getting with your purchase will allow you to use the cub year round (moving snow, dirt, multch, etc.), not to mention the wheel weights and other items. The parts alone on the tractor quickly add up to over your purchase price. I just saw a 14 hp Kohler off a cub go for over $400 on E-bay not too long ago!! But ultimately, it is your $$ and your choice. I just wish to add with what others have been saying, that if you do purchase an older cub, then you won't regret your decision!!!
Keep us posted on whatever you decide. Lots of luck to you and yours and WELCOME!!!!
Cub Cadet 123