Best case, whenever anything religious comes your way just respond with nods and gestures. Should things get to serious, pretending is your best bet.

Worst choice would be to either confront or claim to be confused about it (because that gets you special treatment from you know who).

As long it's a short visit, you'll do just fine.

Make your own plans , that won't lead into problem areas . Plan to treat her . Take her to local exhibits , maybe art exhibits , local arboritam , museum , take her out to a Sunday brunch , take her to the beach . If she pushes religion , tell her that you are admiring his creations .

Before anything, she was your Mother....... How hard is it to tell her what she wants to hear?

I have a friend whose mother is part of the We- Free's ultra strong sect - My friend says she just girds herself up on visits for ' la la land where the moon is made of blue cheese ' She says if she is girded enough, it works as she does love her mum. Just simetimes has to use excuses to leave early.

If push comes to shove just say "whatever let's you sleep at night"

If you expect mom to behave like she does, and she does, then you should be Ok with it. Maybe even chuckle at how close these 2 match.
when her behavior doesn't match your expectations is when you should emotionally react.