Plan your trip. Decide whether you'll be mostly cooking or eating out as you travel. Consider what activities you'll do, such as swimming, rafting, or hiking, and gather the equipment needed for those activities.
Start your organizing in the kitchen. If you're planning on doing a lot of cooking, make sure you have all the basics necessary. It's a good idea to have a simple meal plan ahead of time so you know what kinds of kitchen equipment you'll need. Even if you don't have a meal plan, you can bring a set of basic items like a medium-sized skillet, one large and one small saucepan, a nine-by-13 baking dish, a crock pot, serving and mixing utensils (wooden spoons and spatulas), an electric beater, and any other items you use on a regular basis in your home meal preparations. Also make sure to have two sets of dishes for each person going on the trip.
Store all items for activities in any cupboards or bins in the travel trailer. Organize them in a way that will enable you to easily access what you'll use first or most often. For example, if you're planning on doing a lot of rafting, and only a little hiking, keep your raft in a place where you can get to it and put it away easily. The hiking equipment doesn't need to be as much of a priority.
Use bungee cords, milk crates or other methods of securing small or breakable items while traveling. Things will shift while you're driving, and if you can contain and minimize the movement, you'll be less frustrated later when looking for a missing item or replacing something that broke.