Some thoughts on range. I think the C28 has 100 gallons of fuel and gets maybe 2.3 statute miles per gallon at cruise? Leaving 15% in the tank, the maximum range at cruise would be 195 miles. Of course if needed you could run at 9 MPH and get more range.
The longest interval between reliable fuel stops is between Shearwater Resort and Prince Rupert, 205 miles, however on that leg, fuel is usually available at Hartley Bay and Klemtu but hours and availability might not be as consistent so one should double check those locations before taking on this section.
If you wanted to go from Petersburg to Juneau and in between visit both of the tidewater glaciers at the end of Tracy Arm, that would be about 200 miles.
If you go around the west side of Admiralty island (to visit Warm Springs, Hidden Falls, etc. the distance from Petersburg to Tenakee Springs is about 145 miles. IF Tenakee isn't open (limited days) then Petersburg to Hoonah is 195 miles
One learning was that to get better economy we reduced our water load by a lot as we were able to replenish our water supplies at pretty much every place we got fuel.