Welcome to iRV2
Sorry your first post is about problems.
You appear to be having issues with both chassis and coach systems , so you might have a couple of problems .
A few question , you say no start , and verified no fuel pressure ; so I'm assuming the engine cranks over , but won't run . Correct ?
Do you have a volt meter and / or a 12 volt test light ?
Do you have any manuals for the steps and levelers ?
Manufacturers names for those systems?