The original batteries will eventually corrode - you'll want to take those out and clean the contacts thoroughly if you haven't already to stop the further spread of corrosion on the battery compartment / analog board edge.
Dying RAM chips can be a pain on the 128k, but until one dies, I personally would leave it be.
It can also be a good idea to check / refresh the solder joints on the analog board connectors and flyback transformer every once in a while, as they'll crack over time and cause intermittent video issues. Be careful with the temperatures as you do this though - it can be easy to melt a connector out of shape. I've had success in the past by doing this while leaving the connector plugged in.