Oh man! That is a bummer :( Leighton used to be like that but I suppose after enough times being put in there, she worked it out! haha... poor kid!
Yeah the pack and play doesn't work with her she will scream for hours if I would let her.
Jules.... my suggestion would be to invest in an inexpensive "Pack N Play" and use that at your MIL and sister's house to keep her place of rest consistent. This is what we do with Leighton and she never has had any issues. We can put her down at anyone's house and she is fine. And, I agree... use the CIO method while you are home with her for those 2 weeks.
Does she scream when she is in her crib for "quiet time"? Mady doesn't fit in those blankies she is tooo long!. We cried it out this am for about 15 minutes and she was out. My only prob is she sleeps in a adult bed when she is with my sis in the am, so that doesnt help.
Hayden gets up at about 6:30, we sit in bed until 7:15 watching the beginning of the Today show, then head out to the living room. She has breakfast at 7:45 and nap is at 9/9:30. This morning nap goes from 1 h 30 to 2 hrs typically. Then we have our window to get out. She is back down at about 2:30 for another 1 hour to 2 hours. If she is not tired for her afternoon nap, I let her "hang" in the crib for quiet time. I do the same things to prep her for naps - put her "snuggie" on - that vest-style blanket that zips, play light music (baby Einstein) in the background and give her a bottle. Even if she is sleeping in different places try to maybe keep these things the same - same time daily, same blanket, same music and maybe a bottle. I hope that helps! I sometimes fear I am too structured with Hayden, I wish I had more opps to have her sleep on the go....
I think using the cry it out method for naps is good too. I did the same thing for Jack and I rarely have any issues with his naps or bedtime. Since Madasyn sleeps in diferent locations throughout the week maybe you should travel with some comfort items. For Jack he has a couple of blankets and 3 soft animals in his crib. I want him to be able to snuggle with things but not treat his crib as a play area. When we travel to other locations (ie grandparents) we bring all his comfort items. This way he relates those things only to sleeping. I never bring them out to be meshed into his daytime play toys. Doing this worked wonderfully at both grandparents' places and all we did was interchange his crib for a pack n play. Also we neve rlput Jack in his crib unless it is time for a nap or bedtime. This also helps him associate this area for sleep only and not for play.
Hope some of this helps.
Good luck! Hopefully it doesn't take you whole two week vacation to get into a schedule.