Sadly, not everyone has access to the Chaosium published rules. However, not all is lost. GURPS is another system which could be used for Ringworld and this is the place for adaptions or conversions to GURPS Ringworld - using the point based system of GURPS and GURPS Space.
John Wood is busily creating GURPS conversions for Ringworld Role Playing.
A guy called Rex Stardust has publihed the character creation notes for Kzinti and Puppeteers Steve Jackson Games GURPS website. Scroll down to the bottom of the page.
Illustration © 2004 Louis Wu, Chmee and Teela Brown investigate a floating building in Ringworld Engineers (Novel by Larry Niven)