At least the MAILTOURL you don't need to hack in the Perl.
You can do the kinds of follow-up URLs you want straight off in
the resources. For an example, study the follow-up link in the
message page setup in
http://www.access.digex.net/%7Easgilman/ava/html/headless.rc
with examples of output at
http://www.access.digex.net/%7Easgilman/ava/html/
This was done for MHonArc 2.0 . As I recall there is more and
better stuff in 2.1 that I would have used but I don't recall at
the moment what. Check the "what's new" for 2.1.
-- Al Gilman
