What would you do..I need some input!!?

I'd appreciate some input here. I do not need nor do I want opinions, preaching or 'shouda, woulda, coulda's'. I simply would like some intelligent advice. O.K.,,,Here goes. Several years ago (13, to be exact) I relocated to my small rental home that I am still living in. Within a few weeks of occupying my little house, there came to my back door a very forlorn, obviously stray and more obviously pregnant black kitten. I say 'kitten' because she was so small I doubted she was fully grown. I made her as comfortable as I could on the back porch, fed her and went to bed..Upon waking the next morning I discovered she had given birth to one solitary kitten. Oh dear!!, what to do. I made her as comfy as a new mom can be, but I could not bring the new family into my home. The reasons are not important..just be ured that this could not be done. So.. I did the next best thing I could think of. I probably should have minded my own damn business and let mama and baby fend for themselves, but I didn't. Hindsight...etc.... anyway, I bought a chain link kennel, 8'X10' and 4' high. I filled it with fresh hay, an airline crate for shelter and several tree limbs for exercise. It was quite safe and comfortable. I had the kitten, "Snot' ( really was a snotty little brat since he was the only 'kid' neutered and he and mama lived a very secure life. You must understand I live on a county road that is the main artery from point A to point B. Many times I have found some of the other strays I had been feeding had been killed on the road. Stray cats are not known for longevity. Anyway, the years have gone by..Snot and his Mom have been safe and secure in their enclosure.The stray cats come and go. I feed them...they occionally drop a litter and I have adopted (rescued) three kittens from three different abandoned litters. They are all house cats now( spayed/neutered) and beautiful. Meanwhile, Snot and his Mama are apparently doing quite well in the world they have adapted to. Well, all good things must come to an end. Last year, Snot's mama ped away. She was 13 years old. Now Snot is alone. Now he is 13 years old. My problem. I cannot bring him into the house proper. He is too old to expect him to adapt to a life indoors. At the present time I have 4 rescue cats, a rescue greyhound and a geriatric Chihuahua. I have been so tempted to just open his kennel door and let him run free, but then realize he has no skills. He doesn't realize what a highway is or that a car can kill him. Of course I would continue to feed him...at least place his meals inside his kennel and hope he would return to it to eat...but I can't be sure. He cannot protect himself...he is not a fighter. He's been neutered and has no idea that there are male cats who would probably kill him. Then I'm thinking, I have deprived this cat of a free life. A safe life..yes.. a life where he did not have to worry about his next meal...yes. I just don't know what to do. I have just put some fresh Bermuda hay in his kennel...he LOVES fresh hay! What would you do...keep him safe in his kennel??...or...Let him be a cat for once in his life and set him free?? Again..no preaching..I do not need any recriminations..I've already done that enough...