Thanks, Ludonaut! I grabbed the (~49MB) 2018 zip and had to do some shuffling around of the file structure to get them to load. Maybe I did something dumb to get them not to load properly, I don't know! Whatever happened, this is how I fixed it.
- Extract contents of zip to a new folder
- Create a folder in the new folder called "18" (minus quotes)
- Move "softs" folder into "18"
- Move index.htm into either img or Images
- Open index.htm and fingers crossed everything should now load