For $2k thats about the best W126 you are going to get. It will need work but it sounds like the basics are their.

Since the car has been sitting I would right away do:
All fluids and filters
Battery
heater hoses and belts
inspect suspension
spark plugs
engine and trans mounts may be due check them.
tires
repack wheel bearings
full detail

Then inspect the car and figure out what else it needs. I would plan on doing the timing chain within the year.

Figure $2k for the car put another $3k into it and you will have something.

__________________
2006 CL500
2009 C300 4matic
1969 280SE
2023 Ram 1500
2007 Tiara 3200