2552 here, not 2351 but mine is hardwired. Came that way from the factory but does not seem to be a difficult project. Mine is located under the drawer of my rear dinette which would be under the driver's side bed on a standard 2552. It is installed just inside from the exterior shore power plug.
As Keelhauler notes, if retrofitting, it might be easier to wire it in just before the converter. Both would work depending on where you have space and access.