For those of us that have big planes and don't have a trailer, getting them to the field can be quite a task. Here are a few methods that I have used to tie my planes down and get them to the field safely.
Prior to getting a vehicle that would allow me to transport my planes within it, I would take my planes to the field using an open bed truck. I made a simple tie down system using by using a sheet of plywood then securing some PVC pipe brackets in various areas to allow me to tie down multiple planes.
I prefer to secure the landing gear as well as the tail wheel or the tail of the plane. This can be done with bungee cord, just keep in mind that if you are wrapping the cord around the fuselage to not make it overly tight and damage your plane. Something to consider is that when using bungee cords your planes do have the potential to shift forward and backward when breaking and accelerating. It is important to keep this in mind so the spinner or rudder do not get damaged.
I Found these straps at Home Depot for a couple of dollars a piece. I really like using them because using the the carabiner can be attached to the eyelets on the floor and then the velcro straps can be secured around the landing gear. This eliminates the movement that a bungee cord allows reducing the potential for damage.
I like to use these on at least one of the three points that are tied down, to ensure that my plane does not shift during transpiration.
Sometimes we do what we need to do, you can see here how I have the tail of my 40% sticking out the back of my truck. Some items to note. I use the 2" blue painter's tape on the elevators and rudder to prevent them from moving while driving. Additionally, tie the tailgate down to the bumper of the truck to ensure that it does not bounce the tail of the plane while driving. You can also see in this picture how I have used the velcro strap mentioned above to secure the tailwheel to the bed of the truck. The front of the plane is being secured using a wooden dowel through the phenolic for the wing tube. On the ends of the dowel I used the screw in eye bolts to provide a tie down point from the plane to the bed of the truck.
Obviously, it is far better to transport your plane(s) within an enclosed area to protect from the elements. Sometimes that is just not possible. If you have to use an open bed, just keep an eye on the weather and do what you can to protect your investment.