I am not so sure about the hygroscopic properties of engine oil. But still, everybody recommends oil change once a year, regardless of mileage. Apart from that - greasing the front suspension of course. The rest depends on what was done at KH. 600 miles is not that much, so I do not think there is much to be done. But as SALMO says, the brake fluid is very important, specially if the car is not driven for a long time. Brake fluid IS hygroscopic, and needs to be changed every two years or so. Apart from that: a spanner check, thightening every loose nut you can find. There will be some, believe me. Check for chafing, check the hood, etc. A nice way of getting to know your car.
