In message , at 23:44:49
on Sat, 27 Nov 2010, John Ray
remarked:
A friend has to travel from Plumstead to Euston on Monday morning; she
has an Apex ticket for the 1007 to Liverpool Lime Street, so does not
want to miss that train.

It seems that she can take a Southeastern train to London Bridge and
try her luck on the Northern Line, or alternatively take a Southeastern
train to Charing Cross and go for the 91 bus. Does anybody have any
suggestions, please, as to the best course, and how much time should
she allow for the connection from London Bridge or Charing Cross to Euston?

I'd suggest taking Thameslink from London Bridge to St Pancras, then
walking. The exit at St Pancras is on the west side of the station and
there's a back-street route to Euston.
--
Roland Perry