Here is link to pickup truck cake I made: http://cakecentral.com/modules.php?name=gallery&file=displayimage&pid=503843
If possible get a good straight on side view, front view and back view of the pickup. I used then enlarge the pictures-especially side view to the size you need to get the over all shape of the cake.
I stacked couple layers on my board, held up the side view and cut away the excess cake to get the profile of the cake. If you can build a cake stand that ellevates the cake of the base board so that it looks like an actual pickup and not sitting flat on a cake board. Take my word this adds alot of wow factor to the non-cake people and really easy to do.
Hope this helps some.
I agree- get as many views of the truck as possible and then take them to kinkos to enlarge them to the size of cakes you are using. I lamenated the pictures of my Mercedes for future use. I used a couple of pieces of foam board to elevate the cake onto the board so that you couldn't see the lift. Carve the sides using your picture- I placed it right onto the side of the cake and cut from there. It gave me a great guideline. From there, it's a lot of tweeking from looking at the pictures head on and from the back.