I can certainly do "Course To", "Course From", and "OBS" on the 480. These
are all minor variations on what you're describing, with OBS being the most
exact match. I'm not sure, however, if the software will let me do those
things on an approach.

Like any other instrument failure, the hard part is recognizing that there
is a problem. Flying partial panel isn't really that hard; the trick is
noticing that the primary instrument has gone TU and not following it into
oblivion in the first place. Once I figured out something was not right
with the GPS (because the CDI and map displays disagreed), there were lots
of ways to fix it. The trick is noticing in the first place.

This is why those involved in the human-factors aspects of RNAV have concluded
that it is next to impossible to manage "curve balls" without a good moving
map. I wouldn't characterize your circumstances as an instrument failure, but
it certainly was a setup for a route discontinuity.

I further checked it with the Garmin 530 using the 530 in conjunction with a
Sandel EHSI. The correct (or best) solution in that case was to go to OBS mode
and set a course of 242 as you worked through the delay "vector." That
resulted in both a magenta line on the correct side of the VOR station and, at
least with an EHSI, correct CDI sensing. Then, when I turned inbound (at about
12 miles) and intercepted the 242 track I cancelled OBS mode. Then, I had to
line select the "PT" to GFGUY" flight plan leg (direct, direct, enter) and I
was all set, just as if I had rolled out of the procedure turn.

It works okay with the OBS set to 062 except the active track is white, not
magenta because the magenta line extends from the VOR station to the southwest
along 242. But, that still works, but is a bit confusing.

It could be somewhat different with a fixed CDI. I don't know.

Bottom line: unlike VOR or ILS, being qualified on RNAV equipment "A" doesn't
give anyone a franchise to operated RNAV equipment "B" or for that matter "B
through Z."

And, think of the issues ahead with the advanced procedures like the one I
posted for DCA.