^ I agree with Mike. Don't just grind and refinish.
@TT: OK, it's cheap for you since you have all the tools available already.
I was under the assumption he was starting from scratch.
It looks like there's probably a lot under the paint which means it could be very serious. Then again, it also might be just surface stuff like what TT said.
I lean towards the sandblasting route if there's no chunks of stuff falling off or stuff rusted out of shape. It has treated me very well although you might find it troublesome.
Good luck.