it is possible but money is a huge concern, if you get a factory spec finish your gunna pay out of your asshole, but if you do get the frame and waht not rust fixed its not gunna give you the lower hand on anything you wanna do with the car.
anyways i do have a recommended shop by my house that does frame rails and floors with under body spray for 200 bucks cash, 250 max ifit is bad. pm me for shop details.
yes just like our drift car cut all the route away i use 1/4" plate , very good for structure. i know what your saying some people just tack sheet metal over the rust. not me, anything i do is to its best no horse shit.