Ain't nothing wrong with having a rock slide. i own one and still run it around the back yard. i have done some upgrades to it and it's still running. it's also what got me in to rc crawling. i don't have any tips for making a cage but this should help out some.https://www.youtube.com/watch?v=i3lPRw3kt3o.
hello and welcome to your new addiction.
if it's a new one the first thing you are going to need is servos.