Lionspaw has done first what a lot of people ended up doing, and mounted his whole unit on plenty of mass, as R. A. Lister recommended over 70 years ago. If your motor and base,gen etc, are floating then all attached ancillaries need to be mounted remotely on flexible connections or engine movement/vibration will flog them loose and cause much expensive grief. Not many alternators will survive vibration for more than a short time. Perhaps OK for short term standby runs, but not a long term solution,
Regards, Combustor.