When it overheats, run your heater on the highest setting and see if that slows the temp crawl down at all. If not, bad water pump. If so, radiator is still clogged & should be replaced.
I do fear for that engine with a visit to 260 though... Hows the oil look?
I would also have a combustion gas test done on the coolant. It checks to see if there's disolved combustion byproduct in the coolant with a simple dip test of the coolant.
'04 Freedom Edition HO & '04 Overland HO (previous '00 Laredo 4.7)