In message , Knotso
writes

I'm visiting London in a month -- for the first time -- and staying with a
friend who lives in Greenwich. Pondering the tube map from Heathrow, it appears
to be something like a 2-hour ride from the airport, to Green Park, to the
Jubilee line to South Greenwich. But then, I have no benchmark to judge how
long a ride it really is. Can anyone provide an estimate?

45 minutes from Heathrow to Green Park
10 minutes for interchange (see below)
20 minutes from Green Park to North Greenwich
--
75 minutes total

The Transport for London Journey planner gives timings:
http://journeyplanner.tfl.gov.uk/index.htm
But beware that it can give some rather odd routes - you are better
asking here for details!

I seem to remember that the interchange at Green Park involves quite a
long underground walk - if you have heavy luggage it may be better to
change from Piccadilly to District at Hammersmith (simple cross-platform
interchange) and then pick-up the Jubilee line at Westminster (where
there are lifts and escalators).

However, note that the Jubilee doesn't go to "South Greenwich" - was
that a typo, or can you be more specific in where you want to end up?
There may be better alternatives, such as taking the mainline railway
out to Greenwich from central London (SE London is well served by
numerous commuter lines, and a branch of the Docklands Light Railway,
but is poorly served by the underground system.)

Being conditioned by New York subway maps, I have to admit the London schematic
map drives me nuts. I can't get a true sense of direction of how close a
station is to a landmark. Which leads to my next question ... do any geographic
maps of the tube exist? Where are they?

Not easy to find on the WWW, but there is a quite good one at the end of
the following PDF document (820K):

http://www.londontransport.co.uk/tfl.../marketone.pdf

If you take a look at this you will see how the Jubilee line runs well
north of the main part of Greenwich - although North Greenwich station
may well be a good option if you are going to be picked-up by car.

--
Paul Terry