Mixing traditional base with sweet spot mid volume

Hi I’m about to start my second plan as a trainer road user. I completed sweet spot mid volume took a week off and will start my new plan next week. I will be doing sweet spot mid volume again. I was wondering if it would be ok to swap out my sunday longer TR ride for a long outdoor 50ish mile ride staying in zone 2 power. The route would be 10 miles rolling hills followed by 40 miles of pan flat rail trail with few stops. Id like to fit this in on weekends the weather is good. Any thoughts are greatly appreciated! (40 year old 5’10" 155b mountain bike cat 2)

Absolutely. Volume is almost always a good thing and if you are doing the SS work during the week, then adding a longer ride on the weekends is a great compliment to it.