You’ll need to read the easement to see how it’s described and talk to the City how they want to deal with it. It depends on the City. Some cities (San Diego for instance) will not want to vacate it unless you locate where the line is or relocate it somewhere. If there is no evidence of a pipeline or where the easement is located, you can ask for a vacation, but it is a bit of a process and can take a few months.
Most of my easement vacation work deals with Riverside, so I don’t know how ornery Escondido is. They seem to have an ok reputation (not as bad as Carlsbad and San Diego).
For easements this old, they probably will be willing to vacate it, assuming there’s no visible evidence of where it is.
If you really care about the property, I would research it first. Email me at [email protected] and send me the scan of the easement and where the property is. I can at least give you some help.
To really locate it, though, you will probably need a professional land surveyor. Also, most title insurance would list this as an exception and won’t cover any losses due to it.
Honestly, unless you’re in love with the property, it may be too much trouble to deal with…