I think the forestry commission has provided a cracking solution around here. Their access roads are solid and even enough for some pace, even in the dark with a torch, along with being rough enough to keep the ankles and knees “stabilised”. There are hills of all angles, flat sections etc. so developing a mixed or specific session is possible. They also tend to stay non-slurry even in the wettest weather and the trees take the sting out of wind & ran. It’s also great for flat out sprint sessions when the imagination takes over and convinces you that the rustling from your flapping jacket is really an axe-wielding sabre-toothed bogeyman coming to get you....