Congratulations on the new trailer! Bug screens are good--and you can move them from trailer to trailer if you ever change trailers. Run your heater during your first dry run because it produces a terrible smell and sets off your smoke detector if your windows and doors are not open this first time use--I speak from experience. Consider purchasing an inexpensive cordless drill, socket attachment and socket that is the size of your leveling jacks--makes running the leveling jacks down and up much easier and faster than doing it manually. Take a bunch of leveling blocks on each trip--they can be home-made from 2X10 or 2X12 lumber or purchased (Lynx Leveling Blocks are available at WalMart for about $30 for a package of 10 and other manufacturers are available at RV dealers and on-line). Take a 30amp heavy-duty extension cord, extra water hose, extra sewer hose and a length of coax cable (for TV hookups when campgrounds offer TV) on every trip. A five gallon plastic bucket is always good for carrying water to put out fires. If you are planning a fire, consider splitting your wood before the trip and taking it with you. Make a small tool box to carry with you on every trip--adjustable wrench, pliers, screw drivers, electrician's tape, polarity tester, bungy cords, light weight rope, extra fuses for the trailer and tow vehicle, extra bulbs for the tail and brake lights on the trailer and the tow vehicle, etc. Use large plastic bins to store stuff in the trailer storage areas and small plastic bins to store stuff in the pantry and under cabinets inside the trailer. Following is a link to an earlier thread that has additional suggestions:
http://www.jaycoowners.com/showthread.php?t=600