Hi: Never been in Jan. but went the first week of Dec. and the xmas decorations were fab. and beautiful.
But the drive down hwy 75 was iffy at first, we had to leave a day ahead of schedule because of a huge storm coming the way of our route, we were in the tennessee mountains and they were cancelling everything as pending freezing rain, but we were a couple of hours ahead of it, coming home we hit a snow/ice storm around ohio and the hwy 75 was actually closed when we awoke the next morn, there was ice all over the trees, road etc, but it later opened and boy do those transports go fast even on bad roads, they were jacknifed all over the place and cars off in ditches, we drove slow but it sure was grinding on my nerves, I wanted to stay an extra day but hubby decided to go as soon as the hwy was opened again.
The bottom line about winter driving, if you choose jan, make sure you check, and check again the cities for the route you will be travelling for snow, and allow an extra day either way, in case of bad weather.
Now we have been in May and I love the drive in the spring, as you get further south and start seeing trees with their leaves, yes green grass and flowers, it is so beautiful, stays light longer in the evening than jan, and the weather in orlando in may is really nice, usually in the 80's and some humidity but not like june/july/aug. That is one of my fav times to travel to wdw.
Hope this helps,
Deb.