You'll be just fine with a NA Skymaster. There is no safer or more docile twin available, and its nice and roomy on the inside.
Single engine operations are so smooth and predictable you have to verify the dead engine with the gauges - your feet will still be on the floor. The biggest issue is the loss of airspeed, generally about 20-25 knots. Landing with one engine is the same as with two engines, and you still have a reasonable 300-400 FPM climb rate available in case of go-around.
Negatives? Not the fastest bird in the sky, a few overly-complex systems, and very heavy on pitch. A few embarrassing landings may be in store until you become accustomed to the heavy pitch forces. If you've flown Cessna 180 and 210 series aircraft, the pitch forces are very similar. If you're coming out of a Bonanza, you've got some "getting used to" in your future.
NA models are no harder to insure than any other piston twin, and there are many reports of low-time pilots getting coverage at a "reasonable" rate.
Insurance is the bug-a-boo for P-models. Dr. Dan, who bought one as his first airplane, and myself, a retired airline pilot, would both be required to go to the same annual recurrent sim training. (If Dr. Dan could even GET insurance.)
No credit is given to me for my 1000's of flight hours and dozens of recurrent sim sessions, all in pressurized aircraft models. Off to sim school you go! (says the ins. company). This is true for ALL pressurized aircraft nowadays.
Dr. Dan MUST have paid cash for his P-model, as I did for mine.
CASH IS KING BABY!
You can tell the insurance companies to go suck a rock, as I have, and keep that $15K or whatever it is for MX costs.
And don't start on about liability - No one on this board has over 1MM via their AC policy, and that won't even begin to cover the costs of hitting a bizjet on a ramp, or dealing with any type of fatality event.
Insurance doesn't cover you - its like wearing a speedo!
Listen to how ILLOGICAL modern aviation insurance is - I inquired about getting "not-in-motion" coverage to protect against hail, tornadoes, theft, vandalism, etc. NO COVERAGE if the AC is "in-motion". Most AC insurers, including most of the big ones, refused to even offer me this coverage. And the few that offer it require a liability policy and annual sim school for NOT IN MOTION coverage. Has the insurance industry lost its freaking mind???