Paint and product suggestions for repainting a plastic model?

Hi all! First time poster, into scale models of aircraft so I'm adjacent but don't have the expertise making cars realistic. I like a challenge so I'm customizing a 1:20 scale truck and slant load horse trailer to look like a real one instead of a kiddie one.

My question is what primer I should use (duplicolor sandable?) on the plastic, and then what paints you recommend for the faintly metallic sheen of a blue truck and what paints I should use for the rubberized truck bed and the truck and trailer's undercoating. Also looking for ways to make the wheels look more rubbery, and how to get the railroader dust and weathering powder to stick to that paint when i dirty up the tires for realism.

So basically, the products I'm looking for/my goals are:

• Paint for realistic truck bed
• Paint for realistic undercoating
• Ideal primer for a plastic vehicle
• Paint for a glossy-ish metallic blue like you see on a lot of today's modern trucks
• Rubberized paint for tires
• Best primer for plastics like this
• How to get weathering powders and fine sand to stick to the tires and get into the treads.
• If anyone has time around trailers, realistic paints for that specific shade of white they have and the aluminum doors and latches plus the interior flooring would also be a cool insight, but this is a longer shot.

Thank you in advance for your expertise!