Our old HTT only had a single-stage converter and for dry camping / charging off a generator I needed something better. I bought an IOTA-55 w/IQ4 and used it as a stand-alone battery charger.
Fast forward to the new TT. I mounted the IOTA to the ceiling in the front pass-through after running a switched 110V line to it (tapped off a bedroom outlet.) This left me with a 3' cable run to the batteries. I also put the factory WFCO converter on its own breaker so I can turn it on or off.
So, I can run off the IOTA or WFCO. Or throw the battery disconnect switch and use the WFCO for the trailer 12V circuits and let the IOTA charge the battery.
Overkill? Maybe. It gets tested next week with 5 days of dry camping.