Need advice negotiating holiday travel pay.

[tuhcoolyuh]

Hi there, I'm a relatively new nurse doing shift work for a pediatric home health agency (1900 - 0700 3x week). I was hired specifically for one family who travelled twice a year, so it was expected (though not required) that I would travel with the family for a few days out of the year. My first and only travel experience thus far was a hardship for me. The agency paid only half of my gas, with the expectation that the family would pay the other half (which they did not do on principle - they felt it was the agency's responsibility). It was over 400 miles round trip, and I stayed in a guest bedroom and had to purchase all of my own meals. My issue now is that the family has purchased a second home and wants to spend every other weekend, school breaks and holidays there. It is about a 2hr drive depending on the season through a snowy moutain pass. Riding with the family is not an option due to space and the amount of time they will be there. If I choose not to go, the family will be in a bind and I will lose the hours.The current request is working at the vacation home over Thanksgiving. I am less than thrilled, but the family will also be requesting Christmas, so I figure I should take at least one holiday. I want to ask my agency to cover all gas and also pay the holiday rate for at least two shifts to help offset my costs and make it worth my while. I will be paying for additional child care and miss the holiday plus spend my off-time away from home. Is this a fair request? How can I word it? My agency does not pay very well and it was difficult to convince them to even help with gas costs. Thanks everyone!