The facia boards have rotted out in several spots on my 1921 house.

I replaced them all a number of years ago, but was unable to prime and
paint them properly at the time. Most of the boards are in fine shape,
but in some spots -- because of problems in the drip line -- they have
rotted. They are easy to remove (just grab 'em and pull them out by
the handful!).

However, these rotted boards are behind the seamless aluminum gutters.
Nothing at all wrong with the gutters and I'd sure rather not pay
someone to replace them.

The gutters are the larger commercial size (the roof is very tall and
made of tile, so they collect a lot of water during rainstorms). And
there are a number of riveted-and-siliconed corners to accommodate the
perimeter of the house -- it's not a straight shot, especially in the
front of the house. Removing the rivets and taking the gutter down is
possible, I suppose, but would be dirty, fussy work and is likely to
damage the gutter channel. And I'm working alone.

I'm thinking I can pull the long nails from the gutters (they go
through the facia board into the ends of the rafters) so the gutters
are loose, then prop up the whole line above the roof edge with poles
or braces, then sneak in behind them and install new primed and
painted facia boards.

Does this sound feasible? Can I get away with it? Or is there some
other technique I should consider? Or is saving the gutters a pipe
dream?