Good news on buying it back!
If it were me, I'd pull the engine and strip the frame down to bare metal. That will let you see if there are cracks, folds or dangerous bends in the metal. Remember that we have a member here who sells frame kits that more easily allow you to remove an engine. So if you find damage on one of the top tubes, you might just want to use Frank's kit to replace that section of bar anyway.