Thanks! I think we will go the later week too. Avoid the parks the last few days we are there. My niece is already planning who she's going to sit next to on the plane.
If you get a chance, join us in the
Disneyland at Christmas/Holiday Season Superthread --
HERE - as we will be discussing and reporting on news, rumors and details of the Holidays all year long, and we talk a lot about which things open earlier or later in the season. Any time any little bit of news or info comes in about the season -- even if it is months in advance -- we report on it in the thread (
sometimes before it gets out to the rest of the forum!

). The whole first page of the Superthread has lots of info for you about important dates to keep in mind, food, seasonal activities for each park, shopping, hotel holiday activities, etc. -- but you can always just jump in and join us anytime and ask questions or say hello.
As everyone has already stated, the second set of your possible dates is better in terms of decorations and activities.
Disneyland's 60th anniversary is taking place in 2015, and -- though the details of the new entertainment have not been officially released just yet -- there is a good chance that they will somehow impact the array of seasonal offerings. Some things could be added in (maybe a hard ticket party of some sort??). Some things could be removed (such as the Christmas Fantasy Parade and the Believe in Holiday Magic fireworks). The holiday season could start a little later than usual -- especially if Halloween Time ends a little later than usual. There may not be a Christmas parade taping (just as there was not one this year) but there may be a taping of some sort.
Even though the majority of the in-park decorations will
probably be up by 11/6 -- and much of the seasonal entertainment was already in effect at that point this year (on a soft-launch basis) -- as
figment_jii said, there is no guarantee that what happened this year or last year will repeat in 2015. So the later in November you can go, the better, if the decorations and activities are of interest to you.
If you go during the Nov 14-21 time frame, the holiday season will officially begin at some point right around that time (maybe on 11/13, but it's anyone's guess) and everything in the parks will be in full swing -- but you could, possibly, maybe, miss seeing some of the decorations (and Santa Claus) at the 3 Disney hotels.
This year and last year, the hotels' Christmas trees began to appear about 9 days before Thanksgiving, so you are likely to see those but it's not guaranteed. In the past the hotels have been decorated much closer to Thanksgiving, and this year the giant Grand Californian Hotel lobby gingerbread house did not officially 'open for business' (
whatever that means, as there were no items actually being sold from the house itself) until Thanksgiving day, though it appeared in its pre- and mid-assembly stage not long after the GCH Christmas tree went up.
Santa and the carolers don't appear at the hotels until Thanksgiving as well, and the other (smaller) gingerbread houses at the GCH did not appear in their respective restaurants until Thanksgiving and beyond.