I used LVT from Home Depot, their "Lifeproof" line. 100% waterproof, click-lock, 6.5mm thick. It was glued down using a permanently flexible flooring adhesive that allows for expansion and also removal of damaged pieces.
Note, all planking warranties are void if used in a RV, as far as I've researched, so don't let that be a factor. Still, a product like Lifeproof that provides a lifetime warranty under standard conditions, is probably more durable than one which does not.
Larry, Eileen, and Finley
2004 Alpine 36FDDS
Third motor home, first Alpine, no need for another.