The Job DSL Plugin support the "Perforce Plugin" but not the "P4 Plugin". The "P4 Plugin" has the distinct advantage of working with credentials.
For my requirements "Manual (Custom view)" is the only Workspace behaviour required. This would be a good starting point for supporting this plugin.
Unfortunately the perforce plugin support is already using the DSL syntax p4. Support for the p4 plugin could use the term perforce instead. e.g.