You will find all sorts of info/recommendations at the top of this blog (under New Users). That being said, the best thing to do is to baseline it across the board. Especially since there isn't a maintenance history. Here are some things that should be done:
- replace timing belt
- replace water pump
- check serpentine belt and replace if necessary
- replace all fluids: transmission, engine oil, front and rear differentials, transfer case, coolant, brake, power steering
- grease front wheel hubs
- grease the drivetrain (to reduce driveline thunk)
- check brakes and tires
It will cost some money but at least you will know the intervals once you do it.
Welcome to the family. Pics?