Theoretically mixmaster should provide good enough anonymity if
used with pgp. Most Linux based mailers eg Mutt, include hooks to
process both pgp and transmit via mixmaster.

For Mixmaster to be effctive, messages (encrypted) are passed though
several mailhosts and eventually delivered (encrypted) anonymously
to the recipient.

Regrettably, any encrypted message or any posts to remailers are
going to be like walking around with a ladder on your shoulder in
a thunderstorm.

If things are really that bad, emigration might be the best option.