Even just looking at the first screenshot it looks like you have a fair amount of detail in the level already, but I should warn that if you end up wanting to redesign any of these areas you'll have to also redesign and redistribute the details. I see you also have dev textures, but yeah that's the reason for those - to get the gameplay down before going into the detail work which is time consuming. You can do as much detail as you feel comfortable with, of course, just a tip though.
The sand texture is kinda butt ugly in the nighttime setup, when you get farther into development you may want to use a
blend texture and spice up the scene with some greens, like grass in the more bio-diverse sections of the map (cactuses don't have enough).
I haven't played the map yet but I worry a bit about the flow around the outside parts of the track. The track itself has some basic shape and flow stuff to it, so that should be fine, but during the gameday test maybe keep an eye on how players are maneuvering around the flank routes, or if people even utilize them (ignore the first round because people won't know where they're going anyhow).