So in theory, it works... I downloaded and installed a ruby script for exporting Sketchup models as .stl's from Github here: https://github.com/SketchUp/sketchup-stl
Took about 2 seconds to download and install. Made up a quick widget:
Exported it as an STL, then opened in Netfabb and clicked "repair"
Saved it, then opened it in Slic3r, and hit export gcode.
Now if only I had a printer to test it out on...