Oil Light Popping On

If you change the bearings, you can do that with the engine and crankshaft in the car. In my experience, it is usually just the rod bearings that are worn, but you can change the main bearings, if needed, with a few tricks. Hardest part is dropping the oil pan, which may require jacking the engine up a bit with the mounts loose, and removing the centerlink from the Pitman arm. That would give you a chance to check the oil pump screen for debris and even remove the oil pump to check internal clearances. While in there, also change the rear seal.