Aye! The rust is the biggest issue. The back of the rear wheel arches is the worst area, as Jonno says. If you see bubbling on the rear quarter panel, that'll be obvious.. but also look inside the boot.. lift the carpet and see what the joint between the bootfloor and the wheel arch panel is like.
The rubber mastic on the underbody seam (joint of floorpan with the sills) splits with age.. so look under the car, just inboard of the plastic sill covers and see what it looks like.. basically the front of the floorpan all the way along the car is vulnerable..
Check the brake pipes, especially where the fronts loop under the wings into the wheel arch and the rears where they pass under the car (on the corner of the bulkhead and floor) .. just behind the front left wheel arch. Ditto the fuel lines just behind the front right wheel arch... As the pipes curve upwards, they're in the right place to get shot-blasted from the wheels.
v6 engine should be good. Cam-belts, tensioners, water pump... you name it.. indestructible. Mine's had head gasket trouble though other people run theirs with not a sausage of a problem. Anyways, look in the header tank for poo and feel up the top hose for "hardness" (shouldn't be any). If you're still not sure... and if possible (cold everything) unscrew the little screw on the back of the rad' a wee bit until either air or coolant comes out. Don't take it all the way out or you'll never get it back in as all the coolant ****** out!
You should have no significant air come out (or just a short hiss) before the coolant starts to come through.
All the engine sensors and doodahs are tough so you'll have no worries there. Only feeble one is the oil pressure sender. O/p might read low and hardly move when you rev the engine.. but that'll probably be the pressure sender so don't be too worried.
The coolant and washer fluid level sensors tend to disintegrate and nobody replaces them (£35 each) but the respective warning lights should not be illuminated, even if the sensors are dead.. they fail "off".
Radiator is right in the front line of the warp speed a v6 beast would normally travel at..
..so gets shot to buggery. Peek through the bottom slot and see what shape it's in.. A new rad is getting on £70-£90 depending on whether you have a/c or not.. a/c car rad's are a bit tricky to change.. the non-a/c are not too bad.
Rear brakes may be lazy... You might need to tweak the rear brake bias (compensator has a spring which rusts in a stretched position) or more likely, the rear calipers are knacked. New recycled ones are circa £80 a unit.. or you can rebuild them if that's your thing. If it's just one side being lazy (look for corrosion on the discs) then it could be worth changing the hose as they sometimes fail internally.. but the calipers do go.. so look for rusty discs and don't take the owner's word for it that they'll clean up... They will.. but only after you change the calipers!
Front brakes squeal and you have to clean the sliding pins up now and then.. but not serious.
Exhaust... as well as the back bit, check the front flexi-pipe. They're pretty durable but they're difficult to get hold of. They're about £200 from AR, so it's not a trivial item. Rear box is cheap and easy to find anywhere. Both are fairly simple to swap though.
All the other stuff is like the T/S.. just the v6 uses more of them, particularly brake discs and pads and front wishbones and tyres...