You have a great start on the diorama base and the models are beautiful but, to my eye, it looks a bit over populated with items of interest. If you want the viewer to focus on the Bronco, make it the item of interest; the first thing that people will notice when looking at the diorama. If you want to include the quad runner and the trailer, maybe attach them to the Bronco and make them visually into one item. Then maybe position as sort a backdrop to the people sitting around the fire. Think about what would make a great photo if you were in the diorama taking a picture. You could also consider the option of making a larger diorama with multiple scenes.
Please forgive the unsolicited advice.
I'm very interested to see how this one comes out.
Best Regards,
David G.