Hi there, I don't, well maybe I do mean to be a wise acre but, not owning a 2008 Monaco Knight and with no photograph included in your post and no product manufacturers name given, here is my answer, " ".
A generic answer would be, remove the screws holding the inside trim to the outside trim and every thing but the latch and dead bolt would be separated from your door. While I might choose to remove the entire mechanism and replace it just as insurance of another failure, that is all you really have to do. Of course you then have to install the new lock mechanism.
If you do have a TriMark lock, on the inside of the inside trim is a three digit number. You need that to purchase a direct replacement.
As stated earlier, the door lock should not have any effect on the steps. If you do not have a copy of the manual for your steps, give us the make and model and someone here will help you with the manual. There are about 3,859,263 posts about electric step failures on the forum and in my opinion is follow the manual(if they are Kwikee) and trouble shoot the cause.
I really would like to help but IIA. Insufficient Information Available.
"I travel not to go anywhere, but to go. I travel for travel's sake. The great affair is to go". R. L. Stevenson
David Bishop
2002 Winnebago Adventurer 32V
2009 GMC Canyon
Roadmaster 5000
BrakeBuddy Classic II