I got the Highway Pickup set a few weeks ago, and put it together in the main configuration, (its a 3 in 1 Creator set) but felt it looked a little off. To me, it was way too short a truck for the size of the cab. It also had a really steep angle to the flatbed when loading a car onto it, in its original configuration. So I decided to make it a little longer. I added a 4 x 12 plate to the back end of the flatbed, and reinforced it underneath to handle the extra length.
I am still a little unhappy with how it looks, the wheelbase is a little short still, but I'm not going to mess with that part of it. It looks good enough now for me. I can even haul the Palace Cinema limo on it. The truck is a little bit oversize for minifies maybe?!