You have answered your own question, I think. Either use a standard session and save the minimum cookies required to access the site, or use a private session and enter your preferences every time.
Given that FF is your browser, you may find that Privacy Badger could help, though, even with a private session. You should be able to work out quite easily which domain needs to be red in PB.
it won't help with having to enter your username and password every time, though.
SD