What I ended up doing was writing a helper function to figure out the root path for you given the page uri, the thymol script path (relative), and the relative path from the directory thymol is in to the root path. So, in the thymol.js file code just after the "path" variable is defined, I set the global variable thRoot using the function:
thRoot = getRootPath(location.href, path, '..');
This enables people to check the project out to arbitrary directory locations on their workstation and have thymol still work statically. I was not able to get the configurePreExecution approach to work. It would fire, but seemingly not affect the loaded thymol instance. I might be putting it in the wrong place though.