changing a OM617 lift pump

[doofus]

I suspect I may need to replace the lift pump in my 1983 W123 300TD. How difficult is it to remove/replace, as in-
1) will I need access from underneath the car? (no shop or lift, just a parking lot-but I *could* jack up the front if necessary in order to reach up, although it doesn’t look like great access from the bottom either)
2) are there any special/unusually shaped wrenches needed to undo the three nuts (because of tight spaces or whatever) and-once the three nuts are removed-will it be a bear to get it off the injection pump body, or does it typically come off easily?

I plan on changing the oil anyway, so I’d be draining the oil before taking off the pump. I’m just trying to get some idea beforehand about what I’m up against, time and aggravation-wise. Thanks in advance for any input!