MK is a crowded mess from the 24-1. If you are only interested in the lights and such, I would skip the park all together and just do a
MVMCP if it is still running when you get there. They only sell a special limited amount of tickets for it so make sure you buy way in advance. Spend the daytime exploring all the deluxe resorts and the Christmas them wing they have. Then take a nap and do the MVMCP at night. As for Osbourne lights, DHS also gets crowded. The lights take up such a vast area and competes with Fantasmic, which will lessen the crowd around lights. I would also recommend doing EPCOT during the holidays. Every country has their own version of Santa and talks about the holiday customs of the country. Also the Candllight Procession is the best holiday show of all the parks. A not miss for any Christmas fan !!!
Deluxe resort-exploring/hopping to see Christmas décor - we did this last year and thoroughly enjoyed it before arriving at MK at 4:00 for early entry into the...
MVMCP - absolute best way to see MK décor but avoid ridiculous crowds. Also get to enjoy the Christmas extras (e.g., shows) that are not in the park during normal hours.
Osborne Lights - likely to be crowded at any time in your timeframe, but worth hopping over to see.
EPCOT's Candlelight Processional - if you never do another thing at WDW for the rest of your life, do this. It was undoubtedly the best thing I've ever seen Disney do, which is a pretty high bar. The music is crazy good, and I would imagine that doing it that close to Christmas would make it even better. (Do a dining package so you'll be guaranteed a better seat. I would also suggest doing a later show...we did the first one of the night, and although incredible at any time, I think it would have been even better if it was dark outside.) As fair disclosure, it is very much a Christian-based program, with no mention of Santa Claus, Rudolph, etc....the "celebrity" is reading straight from the Bible, and the massive choir and orchestra are singing and playing songs that fit right along with that. Honestly, I was pretty shocked that Disney would still do that, but thrilled at the same time.
EPCOT's holidays around the world - my daughters nearly killed me trying to get to every country to sit and listen to their holiday traditions as told by dressed-up holiday characters (Father Christmas, Pere Noel, the Three Kings, etc.).
We did something questionable and did EPCOT and then high-tailed it over to DHS for a quick look at the Osborne Lights. Probably only had about 30 minutes to see them by the time we got there, but that was enough and saved us from needing an extra night. I say it was questionable because we were running all over the place trying to catch the various holiday characters at EPCOT, see the CP, etc., all while Dad (me) was denying our family food because we didn't have time to eat! (We did a very early dining package, so we had "dinner" at about 3:00). Thankfully, we slipped into Sci-Fi after seeing the lights at DHS, about five or ten minutes before the park closed, and were got seated immediately and were not rushed at all to get out.
