OH my god! How can you drive a rust heap like that? You need to give me your address, so I can fly out and remove it from your property.
Seriously. If your son is now three, he will spend hours "helping" you under the hood, and he will remember you driving him to sports practice, going to McDs, to school,and will be dumbfounded the first time that you tell him you want him to drive.
I've had my "Mistress" (as my bride calls her) since my son was six weeks old,(he's 24 now) and he almost had heart failure when I told him I was thinking of selling the truck.
Those little bits of rust are easy to fix or repair, and if you can't afford it right now, expose it, treat it with a rust inhibitor, and prime it to stop it from getting worse. As luck would have it, you have a white truck, and there's white primer available. You could do this and most people would never notice.