I have done this on the same engine but in the larger 124 chassis. I have seen this engine in the 201 chassis such as yours and it is really shoehorned in there. In spite of that fact I'm sure you can do it.

There is a special tool that eases the job, without that you will need to remove the belt tensioner which will remove most bolts from the p/s pump. Once you have the p/s pump and tensioner out of the way you will be able to reach all the water pump bolts with extensions and u-joints. The fan must come off before the belt tensioner. Only loosen and remove the outer bolts that hold the fan to the clutch.

When replacing the pump also replace the hose above it that is about 1 1/2" dia by 2 inches or so. Also replace the o-ring on the heater connection and of course the o-ring between water pump and block. Put the block to water pump sealing o-ring in place in the water pump with grease so that it will stay in place while positioning the water pump.

This would be a good time to replace the belt and flush the cooling system.

Good luck,