Your requirement for 5+ bodies will really kill you. None of the 6 place airplanes can carry 6 adults and more than 50% fuel load. In a Saratoga if you carry a pilot and 5 adults, plan on making at least 3 fuel stops.
If you are going to learn to fly yourself,
Go for a C208 Caravan. It' will make the trip nonstop and cross the mountians without too much trouble. Despite the fact that it is a turboprop, it is as simple as an airplane can be. You could get your liscense in a 172, go to training for the 208, hire a instrument instructor to teach you IFR flying while you make your trips and get used to your new airplane. Most seating arangements are for 8 pax with plenty of room for baggage.
Down side is that it's unpressurized, and somewhat slow.
If you are going to hire a pilot to fly you.
Pilatus PC12, or perhaps an older Kingair 90. Both are very close in deminsions, load, and speed. The PC12 only has one engine, and is there fore much cheaper to operate and insure. The fuel will be much more in a Kingair, but it may be offeset by the higher purchase price of the PC-12. Wiht todays fuel prices, I'd go ahead and spend on the Pilatus.