refrigerator maintence, where would I look for water leaks?

If you weren't on the site opening and closing the door every day, the only moisture to freeze on the fins is when you did use the door. That small amount of moisture freezes on the fins and no water goes through the drain tube until you defrost the box. No worries.

When you are up there defrosting, observe the drain tube and make sure the melting ice water travels out of it. That is your insurance against any damage from the fridge defrosting.