RN,

. I'm comfortable enough setting up a Garmin 430 to
navigate to another airport but that's about the limits of what I can do with
one. Don't have a clue about GPS approaches....


Well, you need one to substitute the ADF ;-)

Mainly, read the 430 manual part about loading and acitivating approaches. What
you would do is to activate the NDB approach to the airport in question. After
that, the 430 will guide you through the approach since the approach is in its
database. The CDI slaved to the GPS will give the indications as if there was a
VOR in place of the NDB - in principle (there are some differences in the
details). This together with the moving map (and the track indication) makes it
vastly easier to fly an NDB approach that way than with an ADF.

This all pertains to an IFR certified installation.

--
Thomas Borchert (EDDH)