I think the first sentence nails it.
OP, is this less about your reluctance to leave your DC, and more that you don't like this friend enough to spend a whole weekend with her?
I ask because while I don't have kids, I do have a friend who sounds like yours. A good friend and a lovely person, but very lonely. And her loneliness has caused her to be self-absorbed. (Or her self-absorption has driven people away and caused her to be lonely. It's a rather vicious cycle).
Whenever we catch up, she rambles on about herself, her childhood, her work, her health, and the various dramas that are happening in her life (and she seems to lurch from one mini-drama to another). The last time we caught up for a coffee, her topics of conversation were:
- an infestation of carpet moths in her house;
- her stress at work and her issues with her supervisor;
- her sore ankle, which she sprained tripping over a rake in her garden; and
- a trip to a seaside town she took with her grandparents when she was seven, and all the various things they saw and did there.
I love my friend, but I often come away from our catch-ups feeling emotionally drained, and frankly, rather bored. I'm happy to see her in small doses, but there's no way I could spend an entire weekend with her. (And she has asked me to travel with her before, and I've had to come up with excuses to decline).
OP, perhaps your friend is similar?