Parents expect me to go to Church

As a grown adult and a diamond scholar, I feel like this is a pretty low-level question to be asking, but I am struggling with how to deal with my parents in this situation.
I am going on a family weekend trip with my kids and my parents. My parents invited us to go so they could have some quality time with us and the grandchildren.
The problem is that they are very religious and will be expecting us to find a Church and go together on Sunday. They were very controlling with me about this (and many other things) growing up and will still, to this day, ask questions to make sure that I am going to Church now. If I don’t go, I usually just lie or avoid the question to make them happy.
I am so tired of this as it makes me resentful and keep a distant, superficial relationship with my Mom and Dad. I don’t call them much or spend too much time with them in case they disapprove of something that I do or don’t do.
So, I could just go to Church to keep them happy, or I could stand up and tell them that we are not going and they will be devastated, ruining the trip for everyone.
I have been keeping them happy for so long like this. I tell myself that I can just keep it up for a little while longer (they are getting older) and keep them happy.
Any suggestions to work through this?