I hope that you didn't pay very much for this car; it sounds like a lot of defferred maintenance ahead. I hope the following doesn't scare you but your problems are not atpical of an SL of this age and mileage. If you didn't pay much, you'll have a lot to spend paying to get the items below fixed by some one else. If you paid a lot, read this board and get familiar with "doing it yourself...!".
R rear wheel locks up.... NTB wants 2k to replace everything
some new calipers hoses rotors pads?
The rotors, calipers, and pads are not expensive, and neither is the hose set if you go aftermarket/rebuilt. I got calipers, rebuilt, from Advance and they weren't much more expensive than domestic car rebuilt equivalents. Some on these boards say rebuilts are not good, but I'm happy with mine (Cardome). A serious flush is probably long overdue of the entire brake system. Water in the brake system after ~20 years corrodes the cylenders of the calipers.
My opinion, doing these brakes (on post-85 SL's) is no more difficult than doing the brakes on a Ford Taurus, meaning, not difficult.
Anti lock light stays on..broken wire on sensor or dirty/bad sensor??
Your grabby brakes may be confusing the computer, I'd make sure the brakes are mechanically OK first. But the sensors are known to go bad. They run about $100 ea but the front ones aren't difficult to replace. NOTE: this light also lights up with low voltage from the alternator - which can have worn-out brushes on the regulator assembly, which costs only about $20-30 (easier to replace with alternator removed).
Ride isn't very smooth....new bilsteins subframe mount kit, engine mounts?
All good ideas, the first things I did. The front subframe mounts made an enormous improvement. One of my motor mounts was crushed, one broken - and I had less miles than you do now. It is thought that bad motor mounts contribute to radiator failure, with the hose being pulled by the engine and breaking the radiator neck.
S L O W power window motors
They just are. You are accustomed to modern US cars.
Engine idles high ...hate to put into gear. i have ordered an idle control valve
You might get lucky with this, but there are a lot of other possible causes, ranging from very cheap to very expensive. This is a must fix.
a/c doesn't work..after looking at other post maybe a t-stat switch?
The A/C has a low pressure "enable" switch, which by design disables A/C if there is insufficient refrigerant. The fix could range from filling with Freon (and probably a new receiver/drier) to an entire replacement of the whole system, which is not cheap. Opinions differ on R-134a conversion - but there is no question that R134a is less efficient and this system was marginal when new and working perfectly.
If you read these boards you will see that timing chain and related components (tensioner, guides) should be replaced at 100K. If you have no record of this being done I would seriously recommend doing it or having it done. Read recent posts concerning a 420SEL (same engine technology) that jumped the chain and will cost several thousands to fix.