After a lot of reading and research I decided on this type of lock and latch system.
Closed and locked with a carabiner.
Unlatched with the carabiner hanging on the built-in door handle.
I used aircraft cable so I could unlatch the catch from the inside.
I have no issues with the wire keeping the latch from catching.. I did a lot of testing before I drilled the final hole for the cable..
In the end it took a larger loop and a hole drilled much higher than I originally thought. Everything runs super smooth.
View from inside of the run.
This is the second latch I added to the outside of the run so I could hold the door open for the kids when they free range.
I have 2 of these on the run door. I may switch it to a carabiner. I think it could fall victim to brute force ... I just doubt a coon could get lucky twice.
Get the cheap ones that have spring closures. The raccoons can't figure them out and they are easy enough for children to use. There are different size ones that fit most latches. Several of my sons do rock climbing and have the load certified types that lock closed, you don't want those. They are too expensive and too cumbersome to open. The non-locking type, which have a spring loaded gate, are inexpensive and easy to use. After removing one from the latch, they are easy to attach to the door handle so they don't get lost. These can be found at any sports store, Walmarts, Target, and anywhere camping equipment is sold.
Of note, while carabiners are effective in keeping out four legged predators, they are not so good at restricting the two legged predators. That level of protection is best handled following Mohillbilly's advice, above.
