Number one-- I know it is in murky etiquette waters: I won't host. My ILs (well, some of them) have demonstrated no respect for DH or our home, don't care how many of my kids' toys their kids break, and don't hesitate to criticize everything from my decorating to my cooking or how I choose to spend my money. I'm fine with them when we're outside of my home; I'm just know better than to subject my personal space to their whims and judgement.
The things that make this hard are that we have the most central location and the most space for 20 people, including play areas and entertainment for the kids, so logically we are the best choice to host. The family also is of the mindset that you put up with each other because we're family, so excluding any of them would be considered extremely rude. DH was told all his life to let one particular sister get her way because it keeps the peace.
A couple years ago, DH's sisters all decided among themselves that DH and I would host Thanksgiving, and told us so. DH was going to go along (he and I are somewhat of the same mindset here, but not entirely), but I made him say "no". We haven't been asked again. If my decision means we should never be invited to a gathering with them again, we're fine with that.
Number two: we will choose when we are available. Both of our families were expected to comply with all of the out-of-towners' schedules. We were willing to do this before we had kids, but it got out of hand. Everything changed for us the year that three of DH's four sisters were all in town for Christmas on different days, and none of them were on Christmas Day. So, DH, I, and local-sister saw his parents on Christmas, then came back again to see SIL#1 the next day, SIL#2 the day after that, SIL#2's step-kids the day after that-- it was one of two times I've ever seen them, and SIL#3 the following Saturday. After all of that, MIL was upset that we went to church with my family on Christmas Eve instead of with her & FIL. That same year, I had family of my own come before the holidays for 4 days, but didn't tell any of their plans. They just expected us to wait by the phone and keep our schedule clear for whenever they were ready to see us. Now, we're available every other Christmas to each family plus one more day when we think we'll see the most people.