working on any mast is not all that hard , the most important thing is to have the correct equipment and use extreme caution when removing any component.
You will need a hoist of some sort, chains and blocks or lifting straps. Something to catch oil in and also to absorb whatever spills onto the ground/floor.

On such a big mast i would have a second person there to help out even if it is to just be a spotter for you.

If you were to give a truck serial number and type of mast that is on the truck it would be more helpful. 2 stage duplex? 3 stage triple? pre 2003?