In truth she is probably happy to have someone get everything cleaned up without having to pay them. I would probably sit down and talk to her, explaining that the truck is probably worth several thousand dollars to a collector, and that the roadster may also be of interest to the right buyer, but that those people are going to want to take those pieces and run. I would tell her that I would haul away all of the 'projects', and that I would also be there to help with general cleanup of the overall property to get it in shape for sale. You might even consider offering to get a few guys to help with anything like painting, general repairs, etc, maybe at your expense. You will invest considerable sweat equity in the process, but she will have someone that is truly interested in helping her get things done right to maximize her selling price.
As a point of reference, there was a '32 Chevy on CraigsList around here last summer, all there but a real basket case and the guy was asking $4k getting no interest for months. If you have time to invest, a work project is win-win to me.