I guess I didn't mess up too badly by what y'all are describing -- because while she wouldn't come out from under the car, she didn't run *away* farther than one car until the end of the night. She just wouldn't come out.
Laurabearz -- that's cool that you got to work in a team for catching cats.

You just described exactly what I've been doing, though. She wouldn't even come out for the treats tossed 2 feet away from her (tuna chunks, which she loves). She may have just gotten enough to eat that she didn't feel the food was worth the risk because I saw her go from "foodfoodfoodfood" to "groomgroomgroomgroomnapnapnapnap", which is usually part of the natural eat/sleep cycle of a cat. Napnapnap isn't usually followed by foodfoodfood again for several minutes to a couple of hours.
I've been trying to catch her by having a string tied to the door of the carrier. The problem isn't *catching* her in the carrier -- it's *keeping* her in the carrier. With me 5 feet away, before I can scramble to my feet and get to the door to snap it closed with the locks, she's pushed the bottom corner of the door enough that it bends the plastic door and she runs out. I'm trying to figure out how I could reinforce the door so she couldn't bend it so easily, or possibly tie the string better (like instead of at the top corner, maybe both top and bottom) so she can't bend the door before I get there. The difference between catching her and keeping her is about 10 seconds, if that. If I could get her to eat with me sitting closer, I could catch her. Or if I could just reinforce the door. I don't want to use a different carrier because the only ones we have with metal doors that wouldn't twist so easily are too small to catch her in and are Blaze and Skye's carriers. The carrier I'm using now belonged to Sage. It's bigger, but it's all plastic.
I think tonight and tomorrow night, I'm only going to take food down and see if I can get her to come out and eat with me only 3 feet away or even only 2. If she comes close enough for me to be able to get to the carrier door (if I had the carrier with me, which I won't for the next 2 or 3 nights) I'll try it again with that carrier.
I may also see if my parents still have our old dog's carrier. I think that's a little bigger, and made of stronger plastic with a metal door instead of a plastic one. I know they don't use that with their current dog so if they still have it, they might let me use it, and that would be better than the live trap that I'm not even sure she's heavy enough to set off.
I just got impatient. I knew that I should have just brought food last night -- I've only been trying this for about a week and a half now, and I know the process usually takes a little longer. I just got impatient because I have a place set up for her and I wanted her in it, and I worry about her being in the parking lot every day.
(Oh -- by the way -- I'm taking every precaution I can. When I close the carrier door and lock it, I'll be wearing heavy-duty gloves. I haven't ever tried touching her and I won't until she's been tested and found clean, and I've arranged with my vet to be able to bring her in first thing in the morning whichever morning I catch her and, if noone's available immediately, just leave her there for the day so that someone will be able to get to her and test her for things like rabies, FIV, FELV, and even the mundane things like fleas and worms or other pests. Clothes worn when trying to catch her are going directly to the clothes hamper even though I haven't ever gotten closer to her than 3 feet except the one time I had her in the carrier and had picked up the carrier but had no glove. And I do a full washing of myself when I get inside, and she'll have no contact with Blaze or Skye until she's found "clean" and/or we've cleaned everything up.)