We had the same problem the last time we were on vacation! We brought the pack and play and when we put her in we were shocked to find she could not even fit from corner to corner! lol
We ended up just putting her in the regular bed and tucked the sheet in tight around her and into the bottom of the mattress as well as put pillows all around her just incase she moved. After the first night of me being stressed I ended up sleeping with her just to be on the safe side! Bad thing was is that she now refuses to go back to bed alone- 2 months later! She falls asleep in my bed then I have to carry her to hers when I wake up in the middle of the night! Ughhhhhhhhh- I work on it nightly and still no luck!
I wish I would have asked this question before and I have to say.... I love the previous posters idea of the sleeping bag for special trips and going to Gma and Gpas!! Of course bring a flat sheet to put on the floor under it so she is not touching who knows what!
Stop stressing! It will all work out as long as you do not show you are nervous! Good luck and I hope you have a fun filled memory making vacation! Blessings to you!