Just went through this as a preventative maintenance...

ALL coolant hoses
Temp sensors in cooling system
The 2 hoses from the OSV that go across the top of the intake
Battery
Alternator
All belts
Spark plugs
Air Filter
New coolant of course
Tranny, rear axle, front axle, and transfer case fluids
Front and rear control arms and ball joints
Front tension struts and ball joints
Alignment
Brake pads and fluid

if you have a coolant leak at rear of engine, probably the valley pan gasket
if you're leaking oil, probably the valve cover gaskets and upper timing chain gaskets