When using disk caching with the old style particles, you can use the dynExport command. This command has a path flag, but unfortunately it's a relative path so it will always be cached in current projects.
This works great, unless you have a project on the network and would like to cache locally for faster simulations.In order to get around the limitation of the dynExport command, you need to edit the current projects. Under File -> Project -> Edit Current you can set the particle directory to be a local drive. A full path here works. Once this is set, the dynExport command will save your cache to the new local directory.