Not knowing the service history, I would change all the fluids and fill up the tank with premium gasoline.
Just a short list of things to do:
Start with the motor oil. I use Mobil 1 0W-40 synthetic and a MB fleece filter.
Read the sticky post on the transfer case and change the fluid. I use Mobil 1 ATF.
Change the front and rear differential oil. I use Mobil 1 gear oil 75W-90
For the power steering, transmission, brake fluid and coolant, I recommend using MB fluids.
You will have to buy a dipstick for the transmission to check the level. (ebay or dealer)
Check the air filter and clean the MAF sensor at the same time.
Remove the wheels and check the condition of the brake pads.
Check around the power steering reservoir and the hoses attached to the radiator, the are prone the leak.
Now, wash and wax and call it yours
