Removing the distributor is easy. Take off the cap and turn the engine until the rotor is pointing directly at something like the #3 spark plug. Disconnect the wire and vacuum, then remove the distributor. Now the important part, do NOT turn the engine, so you can drop it back in at the exact same spot.
I'm amazed at the miles on the 230, I never could get one to last that long. Sounds like time for a new oil pump, if not an overhaul.
Here's what I would do. Put in either a can of engine flush or a quart of kerosene. run the engine at idle until it is completely warm, 15-20 minutes, and keep an eye and ear open for problems. Drain the oil, remove the oil pan and pump. I would inspect the pump, but put in a new one anyhow. You will have to remove the distributor to replace the pump. Be sure you clean out the pan and the oil pickup screen. Put it back together, add oil and spin the pump until oil comes out the valvetrain. then put in the distributor and start her.
As for the oil gauge, the easy way is an underdash add-on. My dad's 64 had gauges instead of the idiot lights. His philosophy: "Only an idiot relies on idiot lights."
