You bring up an excellent point, which as far as I'm aware Apple has kept quiet on, and it will be interesting if they explain this at their pre-launch gathering most are expecting to see.
Or if they carefully decide to deliberately not mention it.
What am I talking about?
The maximum distance the Watch can be from the iPhone and still function.
In your scenario, and for everyone else, in home life, this is a major, and I mean MAJOR point that will make a vast difference to how the watch functions for you day to day.
If the iPhone just had to be in the house somewhere, or downstairs where you are, or in the same room as you, or within a few feet of you.
That fundamentally changes how the watch will feel and work for many.
If for example the iPhone just had to be in the home/apartment somewhere, then the watch will be great, and you can just relax when wearing it at home.
If it however had to be within say 10 feet, then it's a mostly dead device whilst you are at home going about your day to day business.
Given how much of a difference in use and function this will make the watch I would hope Apple will explain this reliable distance it can be from the iPhone fully before launch