1. There is no type/brand/model-specific owner's manual.
Pretty standard in the RV industry.
2. There has to be factory-installed backers for the ladder. If it wasn't an option in 2014, for that model, the answer is no.
3. Most are.
Dan-Retired California Firefighter/EMT
and Zoe the Wonder Dog(R.I.P.)
2016 PrimeTime TracerAIR 255, pushing a 2014 Ford F150 SCREW XTR 4x4 3.5 Ecoboost w/Max Tow Package