As you can see, I decided to have a landing and turn in the steps. This merely had to do with my layout, if the stairs are running along the side of a cage it makes much more sense to run them straight on up.

To make the landing, I merely added another 6\\\" piece of the 1x2 to the end of one of the steps. You could either do this, or cut a piece to fit. The suports for the steps are from the 1x4, and were cut to fit. There is one more support that cannot be seen along the back side of the landing.

If you are worried about the cavies peeing on the steps, there are a number of non-toxic adhesives that could be used to glue either coroplast or linoleum to the steps. Or towels could be lain over the steps as well.