hi lisa and welcome to the forums!
just inflate the tires to 65psi and keep them at that pressure (check each morning when cold)
IF you plan ever to drive 65mph or faster that's the ideal pressure.
IF you weigh the trailer and KNOW how much weight is on each tire,
they might safely be inflated to 50 or 55 or 60 psi BUT that's only if you know the weight figures and never exceed 65mph...
most rv tires FAIL from under-inflation
also be sure to check/inflate the spare tire
before the trip!
for scratches here are a few suggestions...
have fun and enjoy the drive!