Feral cats do noone a favor, deal with them by spaying/neutering or get them somewhere that they can be dealt with. They live an awful uncertain life filled with diseases (spreading potentially), and they wreak devastation on native wildlife.
Use the trap if it's what you have, if you can't...animal control.

Contact your local animal shelters, cat adoption centers and animal control, and ask if they rent/loan traps. They should have traps that are safe to use for cats and remember that the more traps you can set at one time the better. Just be sure that someone is around to check the traps often.
Google for more info on trapping cats and if you want to purchase a cage the link below has one made specifically for cats.

Here is a link that might be useful: traps

Thank you for that link. I have two of those traps-- they are what we used for the raccoons. I shall order a couple more from one of my local sources and put them out. I am willing to spay, neuter, feed, vaccinate, etc., but I am drawing the line at any more indoor animals. With the Great Pyrenees, et al, I have all the vacuuming I can handle already.

We had the same situation. The kittens were too small for the Hav-a-hart, so we caught them by putting food in a wire dog crate, and, I kid you not, tying a string to the crate door and hiding behind the back door of the house. When the kittens were all inside, we pulled the crate door shut with the string. The kittens were not happy, but they weren't strong enough to get out.

We later got Mom with the Hav-a-hart trap for cats. We had Mom neutered and vaccinated and then let her back out, fed her, got her a Feral villa house to stay in. We did the same with her "beau", a male cat that hung around with her. They stayed nearby for a couple of years but we haven't seen them lately.

We actually kept the kittens as indoor cats but I'm with you on the vacuuming thing. There is nothing in my house that has not been graced with cat hair.

It's very kind of you to care for them as you have planned and I wish you good luck.

A friend of mine had about 4 or 5 stray cats showing up at her door a few years ago (a mother and kittens). She was not able to bring them inside, but she did trap them, take them to be spayed/neutered and released them back at her house and continues to feed them daily. They get in out of the weather under her porch and she feels bad she can't offer them better shelter, especially during a bad winter like last year, but at least they get daily food and some shelter which is more than they would have gotten otherwise. Sometimes you can only do what you can do.

It's nice to see how so many on this thread were so kind and generous, and spayed/neutered the stray cats that came your way. Kudos to all of you, and here's hoping you are able to trap yours, kitchen detective!