I'd agree with others - get the brake controller as soon as possible. It makes a big difference - and just being careful yourself doesn't allow for the Yahoos that will cut you off and force a quick stop.
I'd ask for a full tour of the camper - like a housing inspection. If for no other reason than so you know how
everything works (and as a double check that it does work). The manuals are often less than clear (I find the fridge
especially difficult to understand - it often covers several models none of which seem to operate exactly like mine).
Good luck! I'm sure you're going to love your new trailer