Search for CIPA Lens on amazon. I bought one last year. The largest one is only $12. Easy to install and it helps. Not as nice as a rear camera but I can see my towed rig and cars behind me while driving.
History: '08 View, '05 Chinook, '01 Jamboree 24D, '78 Apache Popup, 81 Komfort Tlr,
84 Mazda B2000 'w canopy,
Tent from wedding shower in '96