Eagle frames are prone to rust. I know we had one. Ours was in "really good shape" according to other Eagle nuts. When converting one, to do it right, you need to strip the skin all the way down to the frame. Repair the frame, rust proof it and reskin. MOST conversions do not do this. Use care when buying an Eagle. They also have the best ride (torsolastic suspension) and are ideally suited to adding slide outs since the frame work is so well built and the design is stable enough to handle having a huge section removed without compromising the structural integrity.
This is what a frame in "really good shape" looks like.