If that Jeep is 12 years old, and all you have is a baseball size pile of iron-oxide, that is nothing.
Newsflash....steel rusts. It comes out of the ground as iron oxide, turned into steel through heating to drive out the oxide part, and then spends the rest of its life returning to it's normal state.
The outside is likely free from rust becauses someone kept it clean and dry. But you can't keep the internals of a frame that way. Rain, humidity, etc... get inside the frame rails and stay there.
There is really not much point in removing the rust because, rust also acts as a barier to some degree. I am not saying that rust is good, but if you remove rust and expose bare metal, the metal will just rust again.
If you are a kook.....and I mean that in a sincere, nice way, do this....because you will NEVER find a frame that old with no rust inside somewhere, this is what I would do.
Go to Home Depot and buy a boroscope. They are pretty cheap now. It is basically a rode with a camera. Stick the thing down into one of the ports and look around. You will see how "bad" or "not" bad the situation really is. You can actually take pictures and video of it. Be warned....it will look worse than it is as the light on the scope exaggerates the solors etc.... and will probably look worse to you.
If you want, you could then retore it from the inside out which would perhaps be nothing more than flushing all the crap out, and then coating with the Eastwood product. IF, you have more crime and mud etc...., you may need to cut the frame open in a few spots to allow a place for the crap to go and then weld it back up. You can wash it out with the hose and use the scope to see ther results.
My Jeep has spent all 12 years and 130k miles of it's life in MN and WI and has only some rust and is still solid. I doubt you have any real problems, but you are more than entittled to be a little "crazy" if you want....I love guys like you, because I like to buy your stuff when you are done with it.