Best methods to fix broken tracks

I use wire-wrap wire to fix broken tracks, or to modify boards. It's very thin, and easy to solder because of the silver coating. It breaks easily so some sort of glue to hold the wires in place is advisable, I just use masking tape, sometimes.

I've had the same problem in the past, if you really don't want to etch another one, I'd just solder a jumper wire across the gap (use single strand/bell wire, it holds it's shape better) I've tried conductive pens in the past and they can be a bit hit and miss, not sure about the paint tho, it may work well if you build up a few layers

here's an example -> PCBrepair

It's ugly but it works!

Sometimes it is best to run a wire between the two nearest solder pads along that trace rather than try to fix it in a very tight area. If you do this then put a few drops of super glue on the wire after you are done to hold it in place and prevent vibration from breaking the connections.