Sometimes a battery for the trailer is included but many times it isn't. I have had dealers throw in the hitch as part of the deal but as was stated get a good WDH. You might get by with a dealer sewer hose but look into a good one ASAP. Ask for a propane fill up if not offered and be sure that all appliances that run on propane work before leaving. Even a new trailer might have an appliance that don't work. That should be part of your walk through and if there is no propane the walk through would be cut in half. Also, be sure to ask about maintenance like wheel bearing greasing/packing, care of exterior especially the roof.