Chevy C-10 is a good choice to begin with. First off, it is a classic body style. Second, it is easy to paint. Like painting the inside of a box. No hard to get to nooks or crannies. Lots of space to fit window masks. See you have a set of curved scissors hanging off your pegboard in your...
Traxxas ProGraphix body for your Slash might be a good place to begin. It will take only one color and all the basic prep requirements you will learn. Here is the TRX video and a link to a body. Good luck. Cheers. 'AC'
ProGraphix body