For the spa, I've recommended Enchantment Resort before if you have the budget. I think you can use the spa even if you don't have a specific treatment booked. The concierge can help you with hiking info. A lot of people recommend hiking up the trail on the east side of Cathedral Rock. For something more chill, try Fay Canyon Trail close to the resort. There's also Bell Rock Trail but it gets crowded so it depends what you're looking for. Maybe try Casa Sedona Restaurant in between hiking and relaxing at the spa.