Don - I disagree with everybody here. You're overthinking. She's been hit with a lot lately with the ex's and also her girls just started school.
You've got just what you thought you wanted - a woman who is available for fun (but not too often) and doesn't demand anything of you. Enjoy it! Stop worrying so much!
The only thing I might change is, your default position is to go back to not contacting her. After reading here how many women really appreciate that simple good morning and good night text, may I suggest you just do that? Friendly, supportive, but not demanding. Maybe she is feeling like you're not paying her enough attention and mentioned something about that to D17, who is then feeling defensive of her mom?
The bottom line is - every time you spend time together everything seems ok. So you may just be overthinking/over-reading things in the meantime. Try being consistent - not pushy - with your communication and see if she responds to that.
And as for the cruise - stop worrying about it. Either you two will be good when the time arrives and you'll have a good time, or it won't work out and you'll be in the same place you were initially - single on the cruise with your pick of groupies. No worries.
