As to the question as to what is the best aircraft for touring, there are as many answers as aircraft. If you need it as a business tool, the speed is probably the main criteria. If you're hours building, then it may not matter. A PA24 with 250hp may well work out cheaper per mile than a 160hp PA28 due to the 60% speed increase. But if you don't need a 160 knots cruise, then there are some very cheap options. A friend built hours flying a J3 Cub around the US at 60 knots. He was a flight engineer and they tend to know the value of money.
And another flight engineer told me that if it flys, floats or fornicates, it's usually cheaper to rent! (Polite version).