I use the plywood over the steps for the toddler. Another piece glued to the bottom to act as blocking to keep him from moving it around.
I don't buy into the hype about anything you can do to be safe in an accident in the RV, for you or the pets. They are mobile death traps, the only way to stay safe is to avoid accidents. Pay attention while driving. These things fall apart sitting still, hitting anything is not going to end well, the dogs are the least of my worries.