Originally Posted by oh'mike
you will have rotting wood in the floor structure and fixing the side light won't address that.---Mike----
That's the first issue to address. sy, you saisd you were dealing with other "minor" rot. It might not be as minor as you think, you are filling the rot you can see. Find the source of the water and correct that problem first. Then, if the rot doesn't go too high in that light, a panel and trim plan, while not "truly professional," could be structually and aesthetically acceptable. If this is one of a pair, you'll have to do same trim scheme on other one so they look like they're " s'posed to be that way."
Measure twice, cut once.
Look at the nail, not the hammer. Watch the fence, not the blade.
If you hook your thumb over your belt you won't hit it with the hammer or leave it layin on the saw table.