We took my late MIL *once* to WDW because my son, then 9, begged her to go. This was not a woman who traveled. We paid for everything so that she wouldn't balk at prices, but when we got to the parks she refused to ride anything at all, just wanted to spend her time on a bench with the baby -- who was nursing, so it wasn't very convenient for me to leave her with G'ma, however much that might have been nice. She later told DH that there was no way she would ever travel "with that slave driver" again. (No, I'm not a rope drop person, and we made it a point to only take her to parks in the morning; in the evening she stayed at the resort except for the night we went to see the Osbourne Lights -- THAT, she liked. We even ate really early dinners to please her.)
As long as the people we are traveling with *ARE* people who regularly travel on their own, we can usually manage just fine, with the ground rules that every nuclear family gets a vehicle and a separate lodging, and that no one will will get upset at being left to their own devices.
I draw the line at going anywhere with anyone who has ever uttered the line, "Oh I *wish* I could travel, but I just can't spend money on that." Regardless of their SES, that line clues us in that these are people who really don't LIKE to travel, and are making an excuse that they think we will be nonjudgmental about. Here's the thing, I won't be judgmental of anyone who just says, "Eh, travel really isn't my thing," but don't try to fake it, because it WILL. NOT. WORK. and will destroy our friendship.
