I am definitely not a local and don't have a lot of Legoland expertise, but we did stay last year at the Sheraton attached to Legoland before our
Disneyland stay last July. Here's what I can tell you. July is really busy! We were up early and ready to get in at park opening. They do NOT open early and we were guests at the attached resort (we did have a back entrance that was kind of nice to have). We enjoyed light crowds for about 2 hours and then I felt it was quite busy...busier than Disneyland that we visited a few days later. However, my feeling is that Feb would be really light. July is when ALL kids are out of school, etc.
We have DS who, by the way was born 2/21 (!) who was 4 at the time...he LOVED it. He enjoyed Disneyland but probably preferred Legoland to Disneyland. I personally think that in Feb it won't be a big crowd buster, but I am not a local and don't know for sure. I will say that we did manage Legoland during PEAK season (I think late July is one of their busiest times, but I could be wrong). We managed, but do all the really KEY rides within your first 2 hours. Many rides are just not built for crowds either--they just can't handle maximum capacity loads--i.e. the jousting horses--there are only a set amount, maybe 15 horses, and it takes 3 or so minutes to get around the track. You do the math when 60 kids are waiting.
It is also very important to get there at park opening as much can be done those first hour or so. Also, we didn't find the crowds lifting later in the evening. We waited at least an hour for a few of the peak attractions still. However, they have the playground area, building rooms, 3D movies etc. which were a good diversion to crowds. In all, I would say if your DC is a
Lego fan--it would be well worth it! We plan to go again this summer...I only wish we were dealing with February crowds!!!
I would allow at least 1:20 to drive there. Good luck!