Hi Rich - I do intend to run the TinyCore from a USB. I'll use core2usb once I've sorted some other stuff out.
@gerald_clark - I don't think Persistence is the problem. I only need it to boot once, not multiple times. I might just not be understanding, or maybe not clear enough. An example of how I would want to use it is this: someone I know, e.g. a friend/family member, with an unbootable PC. I want them to then just be able to download one ISO file, and run that either from a CD drive or a USB drive. They then boot into the command line, and type out a couple of commands to interact with their Windows files.
I need it to save files to a USB drive, and edit files directly on the hard drive, but it doesn't need to save any of it's own settings or applications. So, I need a copy of ntfs3g on the ISO right from the start. I think to create a slightly customized version and remaster it? I've read through a decent amount of the wiki, so I think that's what I'm trying to do. Alternatively, with xPud I know files can be transferred directly to the USB drive which will run as necessary. However, I would like this to work for anyone booting just from a CD as well. I guess I'm trying to create a custom tiny rescue disc that's simple to use. I'm good with Windows, just bear in mind I'm relatively new to Linux so a lot of the stuff that's obvious to you isn't to me.