This case comes across as a typical home invasion, carried out by a couple of complete morons.
First and most importantly, I think it was likely done by someone not only familiar to her, but to other people at the complex as well . This would include current and past landscapers, maintenance men, road repair crews, cleaning crews, trailer park employees, and kids that roam around and offer to cut grass. I think this was pulled off by a kid(s) who was under the mistaken assumption that this lady had plenty of cash around the house or had heard rumors of such. They didn't want the credit cards because they are too easy to track and result in video footage many times. Using a stolen credit or debit card these days is getting riskier and riskier.
I think rather than physically assault her, she was herded out to her car and told as long as she kept quiet, she would be okay. She may well have been alive and well when the car was parked and abandoned with the keys in the ignition, with the intention being that she would yell and holler enough that somebody would hear her, and eventually let her go. Due to her medical problems, things may have gone awry and she may have succumbed to a heart attack, positional asphyxia, suffocation , hypothermia, some other medical ailment, or a combination of all of them.
This is most likely a couple of younger kids who were just familiar enough with her to think she would be an easy target, which of course she was. They wanted cash, guns, a lock box, a home safe, prescription drugs, jewelry and/or anything else that is easy to cash in. They may have heard "rumors" about what she had in her home, or they themselves may have done some work in it at one time or another. Since harming her wasn't necessarily in the cards, taking her along and dumping her out in a place where people could hear her yelling and beating on the side of the car, would buy them plenty of time to make an escape. She gets released unharmed, no harm---- no foul.
Another possibility...... This was carried out with a female involved, or, maybe carried out by females all together, who were opposed to physically harming her.