Are they serious? or are they actually deluded? They will be expecting you to commute to where they are staying, with. newborn?
A C Section is MAJOR ABDOMINAL SURGERY. It cuts through all the layers of your abdomen to get a boby out of the very core of your body.
Tell them to do one. Don't agree to anything, no visitors, no trips, nothing.
It can take up to a year to recover from having a baby, no woman takes that year before getting back into doing all the menial labour associated with a newborn but it doesn't negate the fact it's major abdominal surgery. Plus the fact it will probably take you several weeks just to get to grips with having a newborn, that you won't be interested or able to accomodate day trips.
I'd tell them in no uncertain terms, not to include me in any if their plans, and if I deem I'm able - i may invite them TO COME TO ME, for an hour.
If they get pissy, let them, don't change what you've said. You don't control their emotions, you only control how you react to their emotions.