Lots of good stuff here:
https://www.jerrytemple.com/temples-tips/
Scroll down to the 421 section.
The 421 is a great plane, the fleet, like all the cabin-class piston twins, is aging, but that doesn't mean there aren't some nice airframes out there. The geared engines, yes, they don't appreciate ham-handed throttle jockeys, but operated properly they are no worse than any other big-bore turbocharged fire-breathers. Not sure where your comment about "not liking cold weather" comes from, those engines (like any other) definitely benefit from proper pre-heat or heated hangar treatment when used in colder environments.
Renewal lessons in a 421, if you can find one available, will be expensive, but, have fun!