The use of a Murphy bed in a camper seems like a great idea until you start thinking cargo storage space and realize you won't have anywhere near as much in any trailer with a Murphy bed as you would in a model with a front queen walkaround bed with a large passthrough cargo storage compartment below. Our trailer is a short 19 couple's model yet the front storage compartment is huge ...

... and easily contains almost all our camping and trailer support gear. It also has the typical storage below the bed that can be accessed from within the camper by lifting the bed platform or better still by adding cabinet doors for easier access ...

... none of which you'll have with a Murphy bed option.
FWIW, I wouldn't also own any trailer with opposing slides that when both stored in the travel position block access to many parts of the interior of the trailer, as would be the case with that
Sportrek ST222VIK.