Using something like a nylon impregnated paint/rust removal attachment for a handheld drill is a good way to get rid of rust without much effort or damage. After that, hand sanding or using an orbital palm sander will get your surface ready for body filler/primer/paint. I am not sure what kind of work you are doing or how you plan to finish it, but keep in mind that if you are looking for a finished repair that doesn't look like a repair you are going to use a finish glaze at the very least. Removing the rust WILL create an uneven surface.