Difficult chapters

I'm currently working on the 4th in my "Blackbird" series of books, and I just finished a very difficult chapter.  It was difficult on many different levels:

1. It is the final game-changer between two characters, and now I am completely AU ("alternate universe") with no turning back.  Part of me is wondering - what the heck have I done??!!!

2.  The research was pretty intense.  Although I was very well-versed in this particular subject 20 years ago, I had to reacquaint myself with some information.

3.  I use real places in my books, specifically venues, hotels, restaurants.  I don't make that stuff up. That means if I am sending my character to a specific restaurant, for example, I go to that restaurant's website, look at their menu, and figure out what my character would order, and that detail is generally included.  If my character stays at a particular Ritz-Carlton, I go to that specific hotel's website, look at the rooms offered and figure out which one my character would stay in.  I don't just make up names for hotels and restaurants.  Why should I?  If my character visits a little town, I use Google maps to get me onto the street level of that town so that i can see what's there (or not there in some cases).  I look at street names, and sometimes I choose a particular street simply because I like its name, but regardless, the location is always correct for the action required.  If my character visits a museum, I know the layout of the interior.  I study pictures of the museum and its exhibits, what street it is located on, and what is nearby.

4. My characters got to do something I have a dream to do, so I got to live vicariously through them - which meant that my research had to be spot-on.

As I don't write in sequence, however, this chapter has to wait for its proper slot within the book. There is a lot that happens before and a lot afterwards.  Of course, I am still tinkering slightly with the chapter but I am also moving on.