Jim, I speak from experience, LOL!
First of all - MA, that jacket leash is also the best thing I've seen! I hate the figure-8s, I'm always worried about the cat choking if it freaks while outside. And the loop-harnesses - well - Lazlo jumped out of his and bolted. It was a horrible day in my life, and it was the second or third day he was with us. Just goes to show you the value of learning about this stuff BEFORE you try it!
Here's my story. Lazlo was our first rescue. We were caring for his family - they were living in a groundhog hole up in the forest behind our home. Apparently their mum started taking them on excursions, but we didn't know that's what was happening. Lazlo was left behind on the first one. After his crying for two days, our hearts melted, and despite Gary's - well - it wasn't an aversion to cats anymore, but let's call it misgivings about "owning" a cat - and my allergies to cats, we decided to bring him inside. If it didn't work out, we'd adopt him out.
He was crying and crying outside - we brought him in. He cried and cried inside. I assume he missed his family, but at the time we thought maybe he wanted outside (knowing next to nothing about cats). We bought a leash, put it on him, he didn't mind at all. Didn't seem to notice it was there. Being dog people growing up, we took him outside, set him on the lawn, and expected he'd be loving it.
Well - the big ol' Maine Coon stray we were caring for came trotting up just then, and she was NOT happy to see this kitten in "her" yard. Lazlo FREAKED - tried to run - but of course was constrained by the leash. He jumped at least as high as I am into the air - (5' 2") - and after a couple of leaps like that (in a matter of seconds) he was out of the leash and up into the woods. We did not have the opportunity to "grab" him before he bounded right out of the leash.
Lazlo's part of our crew (the grey tabby with a "coffee-stain" around the front of his mouth and nose
), and he's happily living inside now. I laid up by the groundhog burrow all afternoon - for HOURS, talking to him, crying and pleading. He finally got hungry enough to come over for a bite of chicken. I picked him up, he didn't struggle at all, and we brought him back inside. He never cried to go out again. Didn't even go near the door for close to a year.
Here's the lesson: the type of leash you use is VERY important. I think on an older cat (larger), the cat isn't nearly as likely to "bounce" out of the leash, but I'd be very choosey about what type of leash to use. I would not buy one that has two loops (for front & belly) connected together. I would not buy a figure-8. I like the one MA posted a link to.
You may already be familiar with how to do this, but just in case....
Cats are not dogs! They are territory oriented more than they are people oriented (most cats, anyway). So "walking" a cat most likely means starting with opening the door and letting them explore the steps or stoop or whatever the space right around your door is. Obviously it depends upon the personality of the cat. Some take right to it - others enjoy being outside, but it takes a while and you have to gradually "expand their territory." It starts with the area around the door. The next day it may include a few more feet. It could take weeks for the entire back yard to become "theirs."
I didn't know any of this and just trundled right into it.
I'm so glad you're taking the time to learn about it first! Don't do what we did, LOL!