findPathToVulcanPackages = () => {
  // look for VULCAN_DIR env variable
  if (process.env.VULCAN_DIR) return `${process.env.VULCAN_DIR}/packages`;
  // look for METEOR_PACKAGE_DIRS variable
  const rawPackageDirs = process.env.METEOR_PACKAGE_DIRS;
  if (rawPackageDirs) {
    const dirs = rawPackageDirs.split(':');
    // Vulcan dir should be '/some-folder/Vulcan/packages'
    const vulcanPackagesDir = dirs.find(dir => !!dir.match(/\/Vulcan\//));
    if (vulcanPackagesDir) {
      return vulcanPackagesDir;
    }
    console.log(`
      Please either set the VULCAN_DIR variable to your Vulcan folder or
      set METEOR_PACKAGE_DIRS to your <Vulcan>/packages folder.
      Fallback to default value: '../../Vulcan'.`);
  }
  // default value
  return '../../Vulcan/packages';
}
Smart function to find Vulcan packages

You can either provide a path to Vulcan as VULCAN_DIR env
or set the METEOR_PACKAGE_DIR variable