It looks pretty "fubar". The only thing I can think of for the dents is to heat it from the backside with a heat-gun or something and see if you can pop it back out. Bumpers are tricky because heating them can warp the paint and stuff.
It looks like there is quite a bit of structural damage and is probably glorified scrap.
You're better off just buying something from Craigslist or Ebay and starting fresh.
If you're going to paint it anyway, Bondo makes a bumper repair kit. That should fix up the cracks after you clean them out. maybe a piece of screen behind that chunk missing and use more flexible bondo to make the bumper come back to normal status.
Whatever you do its got to be able to flex, expand and contract.
yea i was looking into heat gunning it out, possibly fiberglassing the back for support of the cracks and bondoing over them. I guess my biggest question is does this sound about right, and what kind of bondo to use, like what does everyone use to shave a bumper...
no problem, but I'd only use something flexible. Having a small patch of normal bondo or fibreglass could crack becuase the rest of the bumper will expand and contract and flex. Thats why I suggested a small piece of screen to use and the flex bondo to build up and shape to make it look new again.
your better off getting a new 98 bumper for like 100 bucks...if you do it yourself you need supplies worth like 50 bucks not to mention time it would take and how good or bad it would come out..body shops charge you easily around 200.