Cass' outfit includes a necklace with a diamond shaped pendant that has a rose in the center (left to her by her father), a brown suede leather jacket, a pink and white plaid shirt with black buttons opened down by 3 buttons, and worn out jeans with a large hole above the left knee. There is something that looks like a handkerchief (or bandana) attached to her belt in the back. Old, scuffed cowboy boots, black gloves, a rattan hat with a black band, and a silver belt buckle to complete the ensemble.
She will automatically equip armor, helmets, and eye wear (eyeglass, shades, etc.) if you put them in her inventory. She will not equip armor or helmets without a DT rating.
If you want to see her hair, equip her with the baseball cap with glasses, then give her a pair of sunglasses (works with Veronica as well). Be careful however as fast traveling will make Cass put her hat back on. She will still have the cap and glasses in her inventory and the glitch can be done again.