I operate regular Outlook, not Outlook Express. It's a bitch to back
up - or am I missing something? Here's how I operate my files:
1) Dell Lattitude 610 Notebook with Windows 2000 Professional
2) I have (2)Flash Drives (FD-A and FD-B) each with 512 MB
3) I do all my work on Flash Drive 'A', not on hard Drive 'C'.
4) When I go on a trip I back-up 'A' to 'B' and to 'C'. 'B' stays in
the office. 'A' goes in my pocket, notebook into the briefcase - my
data are in three different places. No matter what happens, ANY
scenario or emergency - I am covered.
5) Except for Outlook - how can I include it in this sytem, i.e. how
can I back it up from 'C' to 'A' and 'B'?

Having so many copies of Outlook is not the right way of doing things.
You will find it a pain to sync across 3 storage devices namely A,b and c
Here's another way, get yourself a outlook service provider and ask
for a service known as Outlook web access. access your emails from web
has never been easier. You will need internet and internet is easy to
get.
if you are paranoid, keep a copy in your notebook.