I belong to a local hiking group. Someone in the group discovered that I work for myself as a freelance copywriter, and asked me to do some regular work for her. I like her very much, and I've enjoyed the work as well. There are no issues with working for her - she's actually a great client and easy to work with - but now, every time we hike in the group, she keeps asking me questions about my work (for her own personal interest), or outlining when the next job will be, or what the next job will entail.
Hiking is my down time - my leisure time - and a hobby. I don't want to discuss work in that environment. For one thing, I'm relaxed and I find it hard to think on my feet when she's peppering me with questions about word choices, style, grammar, etc., and I stumble over my answers because I'm not in 'work' mode, so I don't come across as authoritative about my subject as I'd like. The other issue is that I actually want to relax and enjoy my hobby, and not discuss work with a client in my own time.
Next time she does it, how can I politely tell her to stop discussing work with me while we're hiking?