yeastcalc.com is your best resource.
let a starter run 24 hours (give it 36 if you can), then 24-36 hr cold-crash in the fridge, decant, repeat all steps again by brew day. so if you go long, 36+36+36+36= 6 days.
it's certainly possibly to do it faster than that, some folks only give their starters 16 hours before cold-crashing. you could also not cold-crash the last step and pitch the whole thing.