Coolant Leak??

I have a 2001 Tacoma 2.7 4 cyl. I came out on Monday and I had a small puddle of coolant under the passenger side front corner - maybe a 1/2 cup of leaked fluid. My truck was parked facing slightly downhill, the coolant had pooled up on the skid plate and dripped onto the road.

I couldn't find the actual leak. I did see coolant where it had dripped from the radiator and ran down the skid plate, I also saw a few drips down the fan shroud. I also noticed that the top of the radiator had a bit of coolant along where the plastic top connects with the metal. I also checked the oil and the transmission fluid, they look fine and no signs of water. The coolant overflow was just about empty, but the radiator looked full. The leaked radiator had a bit of rust color and I now it's been awhile since I've flushed the radiator.

I'm thinking I need a new radiator, so I ordered one online. I also filled the reservoir with distilled water to get me till the new radiator arrived. Since then, I've had no issues temperature and the leak has stopped. I haven't had a single drop leaked since Monday.

Has anyone else had a similar experience? Why would it stop leaking? Am I on the right track of replacing the radiator? Is there anything else I should be aware of?

Thanks for any advice!