I know people are posting that you sound like a spoiled brat, but what they don't realize is the level of frustration you carry around when you have an inlaw that delights in making things difficult and pulling the rug out from under you-I could very, very clearly *hear* that in your post, and to others it may be whining but to us in the rotten in law club, we get it!
Having said that, I regularly knock myself out to give the girls positive, controlled experiences with my MIL that they'll remember as happy times. So, I would say go on the trip with your FIL, he's making the effort, as lame and half a**ed as it is, it's better than nothing.
Which is something I have to keep reminding myself of, on occasion...
Here are some tips to help. Actually, just one big one. Make an itinerary, and email it or mail it to him and ask him (nicely) for input. This way, people don't get unrealistic expectations or make assumptions, two things that always lead to trouble in my family.
Well, one more. Schedule at least one day where you don't do stuff together at all with him-just with your kids and hubby. I call it the decompression day. Trust me, you'll need it after about four days in.
We've had good vacations with difficult people this way, and it's worth it.