I tend approach M4-78 a little differently as I likely to do Korriban last. I do this because I want all of my possible droid party members available to me before attempting M4-78.
In the hidden portion lay minor spoilers.
In order to clean the radiation near the start of the planet, you have to send in a droid. Depending on which droid you send in, you're going to have different dialogue. This makes sense because T3-M4, HK-47, and G0-T0 are vastly different models in personality. I'm leaning towards G0-T0 for my very next play through as he doesn't get enough love.
Back to your question, I suppose my order would be Peragus, Citadel Station, Nar Shaddaa, Onderon, Dantooine, and then Korriban / M4-78.