A small oil leak should not cause any problems on the 600 mile road trip as long as it's not a huge leak and you're not losing a lot of oil at a time.
I've driven vehicles on 800 mile road trips before with small oil leaks and some more worse oil leaks and I just carried some extra engine oil with me.
I would drive 80 to 100 miles then pull over and take a break and then check the oil and top it off and it was just fine.
As long as the engine constantly has oil in it the oil leak should not cause any problems but just make sure the oil is not leaking on the exhaust where it could catch fire.
But if it's dripping elsewhere and only loses a little oil every 100 miles or so then I would continue to drive the vehicle and would not hesitate to take it on a long road trip.
Just stop and check the engine oil often and carry enough oil with you to make sure you have enough to top the engine oil off.
Some cars are not worth the cost of fixing the oil leak and in that case I would just spend the money on extra oil and continue the drive.