The whole deal before was to get the trailer as level as possable because the axles were supported independantly to the frame. If too low or too high in the front the trailer would transfer more of weight to the front or rear tire possably overloading them. Today most all trailers have a equialized suspension meaning there is a pivot point that the rear of the front spring and the front of the rear spring are tied together. This allows the front tire and the rear tire to carry the load equally if the trailer is not riding level.
That being said you still need bed rail to trailer clearance and as said in the previous post, running nose high seems to be very common among us with late model trucks. If your camper has the equalizer on the suspension don't worry about the atitude (within reason) of the camper connected to the truck.