OK. I suppose it's clear that strong and unique passwords at every point will offer the most effective defence. At that point you're trying to make the engineering tradeoff between security that's maximally effective and security that's so inconvenient it won't be used - perhaps that's why you're struggling to find an answer. Best practice is too difficult for you to accept, and you're surely not atypical.
A dongle which plugs into USB and injects unique passphrases as if from a keyboard gets over the memorisation problem. Something like YubiKey. For me, such a dongle would ideally have an integral keypad, for the single strong access code. Otherwise, you have to keep the dongle with you at all times.