I had the locking mechanism in the outside door handle fail suddenly without warning less than 24 hours before we left on our very first trip with our Scamp
An exact replacement was available at a local RV shop. Before I found that, I discovered in a pinch a standard square shaft garage door handle (T- or L-style) will work, too. Most hardware stores stock them. Changing it is a simple matter of 2 screws and a hack saw to cut off the excess shaft.
Just in case "hard" becomes "impossible" on the road...