As was stated, a good coat of your typical Krylon type primer over the whole model is a good start. I would use a grey color primer so no color shows through later.

I used Tamiya x-60 as my base color via an airbrush. This is a water based acrylic and is in my opinion terrible paint to work with. It thins poorly and has odd drying qualities. It worked out ok, but I wont use it again. Testors model masters is a better paint in my opinion.

For the secondary camo red, I blended together a number of enamal Floqual colors, box car red being the primary color to start with..I just lightened it with a tough of white and a bit of tan enamal until I got a color I liked. You can certainly find a variety of appropriate camo colors in acrylic by Tamiya, Testors etc if that is your preference.

After all paint dried including the hand painted tools, weathering and dry transfers were applied, a number of thin coats of Testors Dullcoat clear provided a protective finish to the paint/markings and gives a nice uniform flat.

It has all worn well, even the undercarriage, so I cannot complain.