Man, tough crowd over here on painting! OP, I have done it. Two of my best friends are career auto painters, and another does a ton at home and has a paint booth.
No, I would certainly not get nuts with the prep. If you have any serious gouges, either blend the smooth with a flap wheel or bondo those areas. masking is easy. 3M also makes some plastic wrap that sort of sticks to everything and I would be much easier for hydro lines. Wipe entire machine with a strong keytone. This will remove grease/oil, and break any shine on the old paint. When I say wipe, I don't mean buy a gallon and use paper towels. I mean get 5gal, rubber gloves, a bucket, rags, and respirator. It will not take long but it will do wonders to prep the surface for paint.
I would not even waste my time to scuff the machine. OEMs sure as hell don't! the secret in this is the paint! You don't need extreme epoxy paint unless you really want to, but you do want a qualified DTM. You also don't want bargain barn Alkyd crap! At least a high end Acrylic. Urethane is MUCH better (all cars painted with it). It will shine and gleam but you may not like the price. OEMs use an epoxy paint because the paint is also a severe duty protection layer. Think running machines through tree branches and such.
I highly recommend you do your own paint work. It is not complicated and when you see one that looks bad, that is usually someone just buying bargain paint, zero prep, and zero plan. Generally the equipment DTM paints are single part (open can and shoot) but do NOT do that. Work with someone who specializes in quality paint and request a hardener. It will make the paint flash faster and the paint will be harder and more durable.
Do NOT roll the damn paint on!!!! This is a spray job all the way! The only way I would do it is get the biggest nozzle you can in an HVLP gun. You can now get them at harbor Freight. I would NOT paint a car with one of those guns, but I'd sure paint equipment with it! I would not even waste the time to move machine to an indoor facility. Pick the right day, right after a rain, very low wind, and run a hardener. She will flash in 15min (not tacky).
I will never be in the "it's old, it should look like crap" camp. Fresh paint says you care about your equipment, you likely care about the job.