you are right that it is probably only worth 500 to 1000 max.
Check th A/c.
check the rear axle boots for cracks.
check the archives for glow plug info
glo plugs are the least expensive.
Face it, discount big bucks for rust
and fix it yourself if it is not excessively deep.
rubber lining of trunk lid.
lots of stuff. how many miles?
what else is held together by duct tape?
if no records, its a big gamble.