A Seneca is way underpowered for carrying more than 2 people on a warm day. Engine out capability I put in the same class as an Apache 160 (barely).
A Cessna 310R with a full de-ice package is hands down the superior choice and the best option. Better performance, no turbo's, great single engine performance in all conditions and VERY easy and docile to fly.
160 IAS cruise speeds and 7-10K optimal cruise altitudes. Fuel burn if leaned out is as low as 8gph/eng
DBW