Storkeye,
I've been there and done it with an Archer and your figures look pretty close. Maybe the insurance could be less but that depends on the pilots and the declared hull value.
If you do the graphs you will see that around 350 hours per year is where the hourly costs start to come down.
Edited to add one further thought. The later build Cessnas with fuel injection are considerably more economical. The difference between a 150hp M model and a 180 hp S is 10 ltrs per hour.
D.O.
Last edited by dont overfil; 8th Aug 2013 at 15:04.