Jet fuel truck

For my third model for the assignment I am creating a Jet fuel truck. I set up reference planes with some images that I found. These images weren't very good as they are not exactly straight and I could only find images of the side and back of the truck so I had to use them as best I could.

I started modelling the truck from primitive shapes like a cylinder and boxes. I then began modelling more detail into the box for the base of the truck by extruding, moving the vertices around and adding swift loops. I attached the cylinder to the boxes and used target weld to weld together the points that I wanted to join. I deleted half of the mesh and then added a symmetry modifier to mirror the other half of the truck.

In object properties I set the objects to transparent so that I could see the reference planes through the model.
I added a mesh smooth modifier to the rear of the truck but this smoothed all of the mesh. I selected edges that I wanted to keep from being smoothed and adjusted the crease setting to 1.
When using the mesh smooth modifier I had a problem where vertices would stick out of the mesh I had to reapply the mesh smooth modifier to solve this problem.

To model the cab I started with a box and by extruding and adding loops I created the shape of the cab.
The front of the truck is proving difficult as I am having to model from reference images that I have found rather than using the reference planes that I had set up.

This is the truck so far, I have put the wheels that I modelled earlier in place so I could see how the mesh needed to be modelled around them.