All of the above-
We have done trips with just DH and myself - only 2 # 3 in 2 weeks
Trips with just the children and grandchildren
trips with children, and their friends/significant others
a trip with DD, DSIL, DGC, and DSIL aunt
The Sept trip is going to be the more the merrier one-
Me, DH, DD, DS, DSIL, DGS 4 and DGS 15mo for 10 nights and in a separate unit for 5 nights DH's ex and DD's half sister. Who says we can't all get along?
This one I may need some PD. DD (husband's daughter by his first marriage) is a planner and has been working on the itinerary for almost a year now. I am more of the get up and go where the spirit or 4 yo moves me that day so it could get interesting when we add her mother and older half sister(from her mother's second marriage- she was married 3 times). We get along quite well for things like grandsons birthdays, holidays etc. so hope it will all work out. I did draw the line at getting a GV - separate units just seems more logical and I wanted points left for the Chirstmas trip with my DD, DGD, and whoever else decided to come along. I have already made it clear I do not expect to be joined at the hip every day and fully expect there will be days when the group is spread all over the place.
All in all we have never really had a bad trip since my DH finally decided that with big groups he does not have to be personally responsible for everyone having a good time. Before that we had a few tense moments and I was almost ready to say - immediate family only in very small groups.
However you travel I hope all your trips are as wonderful as ours have been.