I've now put all the things that I wanted to do into EGeoXml.
EGeoXml takes files created by My Maps (and other KML files of similar
structure) and renders them within the API in a manner that exposes the
objects and grants you considerable control over the rendering.
http://www.econym.demon.co.uk/googlemaps/egeoxml.htm
It's by far the trickiest bit of Javascript I've ever written.
The simple way to use it is like this:
<script src="egeoxml.js" type="text/javascript"></script>
var exml;
exml = new EGeoXml("exml", map, "test001.xml");
exml.parse();
If you want more control over the rendering, then there's a considerable
list of {options} that allow you to use a sidebar, control the style of
the markers and info windows.
You can pass it several files at once, useful if you have a My Map that
takes several pages and you'd prefer to see all your points on a single
map with a sorted sidebar.
You can use it with GMarkerManager or MarkerManager, but you have to
provide your own helper function, because I can't guess suitable minZoom
and maxZoom values for each of your markers.
--
The Blackpool Community Church Javascript Team
http://www.econym.demon.co.uk/googlemaps/