10EOZD Generator 2009 44 Sojourn - Coolant Change

[Rocketman]

New to me at the first of the year. Boat has always been fresh water in Georgia and now Alabama.
I need to change the coolant (looks like it has never been changed). Here is the problem and probably the reason.

The generator is placed on the port side of the boat tucked under the back platform. There is about 4 inches of clearance above the generator and there are no access holes in the platform.
After removing the front, service side, and top sound covers; I can barely reach my hand in far enough to touch the radiator cap. No way to remove it, drain the coolant, access the petcock on the rear, fill, reach the bleed screw, or access the anode.

Has anyone else done this job or have any ideas on how to gain access without somehow unbolting the generator and sliding the whole unit out against the port engine?
Even then, it may be difficult to impossible to reach the back side petcock or bleed screw.

I am thinking of just slowly removing the coolant from the overflow tank and filling with fresh each time I run the generator to slowly mix in new coolant and remove old coolant. This will take a while but I think I can get it fresh enough after about 3 gallons of coolant removing and replacing over the summer.

Still does not resolve replacement of the anode but the generator/boat has always been in fresh water and has 520 hours on it.

Thanks