The issue was several-fold and I came across the solution from another post here.
1. WebDAV has to be enabled on the parent although no authoring rules are required. That will prevent access to the parent.
2. The application pool needed to run under an account that had access to the webdav folder. This is because the web.config is housed in the folder. The account needs to have logon as a batch rights to the server as any custom account for IIS app pools requires.
3. The top-level folder required a classic ASP application pool so the webdav folder needed to have a separate application pool running under the native mode.
The site is using the IIS redirect module to redirect http to https. This did not need to be turned off for it to work.