If I understand the issues here, whatever changes are made have to consider the ability of the replacement radiator ….wherever it is placed….. to be cooled by transient air flow through the generator bay. At present, a remote radiator is in place. This system, by definition, has an air handler that sucks the air through the bay and passes it through the remote radiator thereby removing the heat from the engine coolant.
Therefore, it stands to reason you MAY not have an option that you seem to imply…..that of a self contained generator with the radiator on the generator. It is entirely possible that the remote radiator set up cannot be changed due to air flow issues, etc.
Just my thoughts. I do think Power Tech offers excellent tech support and would discuss this completely with them.
Was this air issue a part of the initial question? If not, I respectfully suggest it is a part of the answer to the whole issue of generator selection.
Best,
Pres