@john, I took the same approach, just html/css/javascript, without
making a couchapp.

Especially now that I want to port the app to a browser extension and
PhoneGap for Android, it was the right choice for me to use "plain"
html/css/javascript. That makes the app very portable.

I would recommend jquery.couch. That has all the extras you need to
build couch apps. Documentation for the javascript libraries are on
GitHub, and somebody else wrote a blog post with examples for each
method (Google for that).

Authentication also works via the javascript libraries once the user
has been setup. You could install the plugins into your couch for
BrowserID/Twitter/Facebook for user registration (GitHub). Or use a
server-side script of your own for user registration and
authentication. There are PHP, Ruby, Node etc libraries.

HTH,

Marcus