Interior Paint for walls and bathroom

I have been looking at forums for days and everyone says something different to use. I just bought a 69 land yacht. I am planning to paint walls grey and cabinets black. The bathroom is the ugly yellow. What do you all suggest. Ive painted a couple other campers (not airstreams)... Ive always user killz first. But with walls the soft vinyl..do you sand or not sand? What do you use for bathroom? A spray paint of some sort?



Sorry to ask this when im sure these all have been answered before.



Thanks so much!!!