A double step can replace a single step but typically the widths are different. Worse case scenario you can move the brackets or install new outrigger brackets but it's very doable. Do you know what the width of your current steps is?
A very common double step is the part # LC432682 which is 25-1/4 inches wide which is a very common width. For outriggers then you'd want the part # LC301704 if your current brackets aren't the correct dimension view full answer...
For a powered single step that would fit your 2010 Winnebago Access 31C the Kwikee Electric Step part # LC3711363 would work really great. It comes with everything needed to install including a wall switch as well as an automatic door switch that opens and closes it when the door opens/closes. view full answer...