I've made some test animations using a simple rig to help me think about why and how the creature moves the way it does. It was really helpful because I now see this as a creature that lives in caves in mountains. It will use its middle 4 limbs to hang from the walls of the caves, use all 8 of its limbs to get down the mountain as spider would, and it will be able to raise up and rapidly sprint on the flat ground once its on flat ground. The 3 different move sets allow the creature to be very versatile and lets it move rapidly over three different terrain types. Thinking about this is going to help a lot when I start sculpting.