You'll have to put in a lot of work to unlock the Gnome outfit, which is labeled as ?! in your wardrobe.

First, you must activate the first of two Gnome laptops. Look on Fisherman's Wharf to find a circular seafood restaurant. On the building's north side, find a duct and send the RC Jumper through the opening to reach a gnome and a laptop. Interact with those attractions to find a map pointing to gnome locations around the game world. There are also two 'X' marks, including one that corresponds to your current location.

Your next step is to find 10 gnomes, which are marked on the map and can be found in the approximate areas indicated below. You will need upgrades to access some of them.

Tenderloin: Pawn Shop - Sitting on the shelf at Papa B's Pawn Shop.

Tidis Warehouse - At the Tidis shipping facility, located north from the Palace of Fine Arts, take out the gangsters and dogs that patrol the yard, then check the doghouse positioned near the front gate.

Embarcadero Center: Health Store Roof - head one block north from Embarcadero Center, and follow an alleyway that extends from the park's northwest corner. It leads past a bus stop with rainbow awning. Vault the fence, climb a ladder to some scaffold, then drop your RC jumper into the vent at your feet. Access the Blume control box, then climb to the building's roof. Open the ventilation duct that you should have unlocked with the Jumper, and use that Jumper once again to follow the vents to the waiting gnome.

Soma Freeway Entrance - Look for the on-ramp that accesses the freeway where it crosses from San Francisco to Oakland. Beneath that ramp, you'll find a homeless camp guarded by gang members. Drive a box truck, van, or a lift to the fence along the back of that area. Then send an RC Jumper over the fence to collect the waiting gnome (it is resting in a wheelbarrow).

Haum Data Center - The block next to the HAUM Data Center beneath the Bay Bridge (between SF and Oakland) contains a parking lot and a small brick building (there's a mural of a unicorn on it). Using a construction lift or other raised platform, reach the roof of this building to find a Gnome (and some other toys).

Transbay Center - On the top level of the East block of the Transbay Center, there's a large hedge square in the center of the rooftop park. Using the Enhanced Spring skill (or a tall truck), launch your RC jumper off the shorter hedge next to these and into the walled-off area. Inside is a deeply unsettling tableau and another Gnome.

Rooftop Hot Tub - Across the street from the Stache and Vine near the Mission-Dolores Hackerspace is a grey building with a rooftop patio. This area can be reached either by climbing the storage shed and latticework on the West wall or by using a construction lift found in a nearby gang-occupied yard. Look near the hot tub to find the gnome.

Garden of Peace & Love - A block to the west of the Painted Ladies is small communal garden (with naked hippies). Enter it from the corner where Doobie Donuts is located and climb the first set of stairs on your right inside the alleyway. At the top of the stairs you'll find another gnome.

SF Moma - On the west end of the park across from the SF MOMA, use the construction lift to reach the top of the taqueria. There is a gnome around the corner of the rooftop.

Oakland: Aquaduct - Between Lake Merrit and the Coliseum runs a tunnel that boats can pass through. In the center of this tunnel is a small dock area - climb ashore and up the ladder to find this gnome resting on a lawn chair.

After finding the gnomes, you need to seek out the area that corresponds to the other 'X' you saw on the map. Make your way to the north end of a park located next to the WKZ station. Check in the tent near the area's northwest corner to obtain the new clothes that are your reward for the extended scavenger hunt.