[JimC]

It sounds like you've got a decent handle on both planes.

I'm pretty sure you won't find a well-equipped P model that can carry full tanks, 2 adults, and 400 lbs of stuff under gross weight. It's definitely going to be a rare bird.

If you plan on flying out of high DA airports regularly, I'd pay very close attention to your weight. I literally flew a loaded* P337 out of Santa Fe on an 80 degree day two weeks ago (82 degrees, actually.) It does just fine with both engines turning. I'm convinced that losing an engine on departure in that scenario would lead to a crash if you're going north, east or west (rising terrain) and a very white-knuckled ride going south (terrain descends very gradually.) The book says you'd be climbing at roughly 100'/minute if you're doing nothing wrong *after* you're cleaned up and feathered. The chances of a successful outcome from a failure below 1000' AGL are low, and you know that you have roughly twice the chance of an engine failure. Once you're up at altitude the second engine switches sides and adds safety, not reduces it.

It'll do what you're asking except:
Provide extra safety on high DA departures at gross weight
Carry 2 adults, 400 lbs of wife stuff, and full tanks
Go 1400 nm - even rarely


*The P337 I flew had an empty weight of 3249. Add full fuel (150 * 6.0) and you're at 4149. That leaves 551 lbs for people & bags.