I'd be tempted by the radiation since the side-effects will probably not be particularly dire and it might help slow or stop the progression of your disease.
I agree with Peter. ADT should be the basis of the treatment and you can combine that with radiation to possibly slow the progression. After 18 months of ADT you could make a holiday and start intermittent ADT.
The combination of Chemo and ADT showed a benefit if the patients had four or more bone mets detected with a bone scan. This is the result of the CHAARTED trial and the re-evaluated GETUG 12 trial.