An awning mat, broom and dust pan or small vacuum will help keep the floor clean.
Good point made suggesting you change a tire and drain clean water from both tanks so your sure you know how everything works.
Apparently the neighbor kids opened both gate valves on the trailer that belongs to a friend of mine, so the story goes, but since end caps were on my friend didn't know it until he took the end cap off. It sounded awful and I was surprised he didn't look at the gate valves while getting ready. That shows he doesn't really get it.
Understand how things work on your new trailer. Keep owners manual for fridge and furnace and water heater inside the trailer. Keep tire psi gauge handy.
Pay attention to the roof and do the maintenance in coming years.