Hands down, if you want an airplane that will fly 4 people, with all your bags, and have plenty of gas to get there, or divert for weather: then the Skymaster is the perfect airplane!!!!! Think about it, fly a multi with the easy of a single -- not to mention proficiency requirements mean flying less training flights with a CFI.
Right now I'm even considering selling my non-pressurized and then upgrading to a pressured Skymaster, because they are that good. Maintenance, just make sure you get a good pre-buy inspection; look for things like new fuel/hydraulic lines. And don't worry about overheating, just open the large cowl flaps on the rear engine (I flew into Las Vegas mid day, 105F, and had no overheating problems).
Just know the most common causes of accidents in this airplane: fuel management, taking off with only one engine running, and flying VFR into IMC conditions and then adding icing ontop of it all.
Snrpilot@aol.com