Well, I have managed to get myself to a 403 error, so I guess I'm making progress.
Using the info above and various other places I was able to find that lighty does not care where you put the .conf file, but it does have to be told where to find it when starting up.  I also determined that the .conf file accepts comments prefaced with '#'. (in case anyone was wondering).  Simple facts such as these are what is lacking in the documentation.
Further I discovered that the command switches for lighttp can be combined  as "-tf" rather than "-t -f".  (Also useful information which was not clearly stated).
Here's where I am so far:
In order to maintain convention for TC, I sudoed to make '/etc/lighttpd/lighttpd.conf', then added 'etc/lighttpd' to '/opt/.filetool.lst' so it is saved.
Using the instructions directly from lighty's site (
https://redmine.lighttpd.net/projects/lighttpd/wiki/TutorialConfiguration), my .config is as follows:
server.document-root = "[path-to-desired-folder]" 
server.port = 3000
mimetype.assign = (
  ".html" => "text/html", 
  ".txt" => "text/plain"
)
Running "lighttpd -tf [path-to-config]" gave a 'Syntax OK' response.  This was however despite the fact that I had made a typo in the "server.document-root" statement. (the hyphen was missing).
Running "lighttpd -Df [path-to-config]" gave errors.
Fixed that and ran it again.  Opened OTWeb and pointed to localhost:3000.  403 error.  
With some other [path-to-document-root] locations it resulted in 404 errors.
Obviously I did something wrong, and I suspect that it has to do with permissions.
I have tried all sorts of possible combinations: Using port 80, adding the user and group names as post above, running as sudo.  And and all of the above.  The ports answer pings.