Stay put! The WL has been under various stages of refurbishment (main pool closure & construction; outside scaffolding for cleaning and repair; interior lobby light cleaning and repair) for almost a year and I have stayed there three times during the various work. It did not hamper my experience or enjoyment!
Any effect the proposed construction will have on you would be minimal. You will not be placed in a room in any area undergoing refurbishment. "Noise" will be restricted to daytime hours when you will be at the parks. And the cabins being built along the water are not in close proximity to the comings and goings of the main lodge and pool.
Do a WL thread search on this site and you will learn all about what WL has to offer!
I have also stayed at the Grand Floridian and think you should avoid the additional cost "sting"
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