I've said this before, but I think it bears repeating.
If you don't sticker up your rig, have it all registered in your name personally, scrupulously obey all the traffic laws (including reasonable speed, signaling for everything, and so on), are a very courteous driver (give truckers a lot of room, flash them in when they are passing you, etc.), and drive right past all the weigh stations like you know what you're doing, you will likely never get stopped. Remember truckers will chatter all over the CB if you are flying along or being a jerk, and you'll attract attention.
If you do get stopped, the answer is to be the nicest human being that officer ever met. Explain that you're just headed to the race track for a little fun, laugh when he asks you if you race for money ("I hear rumors that some people do, but for me, officer it's way more out-go than in-come

"), and answer every question with a smile. I've been pulled over once in Iowa (which they say is terrible) and he was ever so gracious -- we were on our way in 5 minutes.
Like most of the time, if you're a jerk not only are you miserable but there are bunch of other people willing to help make you even more so.