The main issues of your questions are:
– you are with family members who may not be as keen as you to go out of their way to go to Mass while they are on vacation.
– this is a trip with your elderly parents so not going might be perceived as not honouring them.
– they want to go to a place where finding mass may be difficult,if not impossible.
So, to begin, let’s establish how factual are these claims. First of all, find out where is the nearest place where mass is available, including foreign language masses. If it is accessible within half a day, it is still plausible for you to excuse yourself to attend. And if it is closer, maybe you can even make a fun trip out of it and convince your non-practising family to join you as an excursion.
If it is far enough to be inaccessible, then the second best option is to see if you can counter offer them another equally attractive location that has a more accessible church.
If that is not possible, then consider how often is this opportunity to spend vacation with your parents and family, and how long are you going to be gone for. If this is a very rare occasion, and you are only going to be gone for one weekend, that would be more acceptable than if you are going to be gone for multiple weekends and there have already been plenty opportunities for the family to gathered together. Look at this as family duty, and an opportunity for charity. But be sure to still keep the Lord’s Day by spending time reading and praying with the readings of the Sunday and making an act of spiritual communion.
One last option many people haven’t thought of. You can also invite a priest to come with you on vacation. That way, he can celebrate mass with your family every day.