It's possible to do 3 day hardcore CS runs, but it won't be cheap (still cheaper than IotMs) or fast. For me, finishing in 4 days means keeping the drinks around to sell and 3 means consuming them, therefore gaining nothing but karma from the run. If you have the following skills (more or less), 3/4 day CS runs are easy.

Powers of Observatiogn (HP) Gnomish Hardigness (HP) Cosmic Ugnderstanding (HP) Fashionably Late (HP) Singer's Faithful Ocelot (HP) Rapid Prototyping (HP) Asbestos Heart (HP) Perfect Freeze (HP) Sweet Synthesis (HP) Object Quasi-Permanence (HP) Eternal Flame (HP) Reptilian Fortitude (HP) Empathy of the Newt (HP) Wisdom of the Elder Tortoises (HP) Astral Shell (HP) Amphibian Sympathy (HP) Testudinal Teachings (HP) The Long View (HP) Leash of Linguini (HP) Spirit of Ravioli (HP) Tolerance of the Kitchen (HP) Bind Vermincelli (HP) Elemental Saucesphere (HP) Mad Looting Skillz (HP) Advanced Cocktailcrafting (HP) Smooth Movement (HP) Superhuman Cocktailcrafting (HP) Fat Leon's Phat Loot Lyric (HP) The Ode to Booze (HP) The Sonata of Sneakiness (HP) Five Finger Discount (HP) Thief Among the Honorable (HP) Master Accordion Master Thief (HP)