I'm the owner of a brand new quad cab....2003 with 247K on it. I was in your position a little over a month ago.

I got it relatively dirt cheap. When I looked at it... the oil was low and so was the coolant, but I'm a brave and determined soul. I currently have the inside semi-gutted to install a junkyard headliner and fix the rocking/sliding seat issue. Might run a few speaker wires over the roof for removable sub while I'm there.

Things I've done...

New radiator, thermostat and coolant. Old rad had slow leak and at that mileage, I can't image the core being pristine.
Oil chng, plugs and throttle body cleaning.
Flush PS fluid and replace with ATF
Transmission drain x2, aftermarket drainplug install, new gasket and filters.
Replaced center seat armrest-cushion with the compartment version
Replaced headlights with aftermarket
Replaced brake caliper, passenger front caliper and flushed brake fluid
Replaced array of burnt out display bulbs in headlight switch and HVAC control

I imagine you'll be doing some of the above. Just remembered that I have to pick up a new PCV valve