If the previous owner was 5" taller, you're looking at quite a bit of cutting and resizing. The biceps and shoulders should be fine. Looks like the forearms need to be shorter. I'd take the extra off the wrist end. Might need to also shorten the shins and thighs. I'd take the extra from the ankle side of the shins, but follow the existing curves of the opening. Take the extra from the thighs off the top, again following the curves. How much you take off will be up to you. As for the back, kidney and rear plates... I'd take some off the lower edge of the back, some off the top edge of the rear and possibly off the lower edge of the kidney. Make sure the top of the kidney still aligns w the top of the front ab plate. There is room to trim the back and the chest at the shoulder, but you'll need to possibly relocate the snaps. Have you considered separating the ab and cod, then taking a bit off the top of the cod? You'll need to reattach the cod w snaps and straps. The seam should be hidden by the belt if this route is taken.
Here is a build for a smaller framed guy and how he made it fit.
Here is a great build from another lady trooper.
*these are only suggestions of what I would personally do to make this fit me if I were in your shoes. There is always more than one way to skin a cat.