ButterflyKisses77 --
If you're looking for someone to tell you that the crowds will not be that bad, or that you will have no problem entering or reentering Disneyland if you hop over to DCA, I don't think that's possible. DCA will
probably not reach capacity, but even that is not guaranteed anymore. Disneyland, very probably, could reach capacity.
I will say -- in fairness, and just to present another side -- that I have, indeed, read comments/reviews from people here and there who have said that NYE was "not that bad" or "not as bad as expected." Some have even said they had a great time, despite crowds in Disneyland. So there are people out there who enjoy it and don't have an issue with the huge crowds, or with getting into Disneyland.
I find, time and time again, that on these boards people want to know how crowded it will be at such and such a time. If we (and that means anyone on The DIS) tell them that it will be really, really crowded, inevitably someone will come back after their trip and say that it "wasn't that bad." If we tell them that it "won't be that bad," then inevitably someone will come back and say that the crowds were "much worse than expected"!

Personally, I tried a NYE trip many years ago -- before it was even an option to hop over to DCA. It was way, way, way too crowded for me -- like the kind of crowded where everyone was packed onto Main Street, smooshed against each other for hours (not even just before midnight, but hours earlier). No space in between each person. No personal space. Anyone who is prone to being claustrophobic would have been very uncomfortable. My friend and I had a rough time even trying to get
out of the crowd because no one would move. After a while we literally had to just barrel through because no one would make way for us to escape!

Another friend took one look at the crowd and decided to head back to our hotel room for the rest of the night.
It was not fun. That experience left me with no great desire to ever do another New Year's Eve trip to Disneyland in my lifetime. Now, many years later, I won't say that I will
never ever do another NYE trip -- after all, the concentration of crowds in Disneyland 'back then'
may have been worse than it would be now, because these days people can escape to DCA or to the hotels or DTD (Jazz Kitchen is having a festive masquerade bash). I could do the NYE trip differently, and maybe hang out somewhere outside of Disneyland. But it is not at the top of my list. I would not
choose to go at that time again, and would probably only agree to it if a friend wanted to go.