Are you just changing the camera or the entire system? After market systems and separate cameras abound on Amazon at decent prices. I put this system on a Roadtrek. 7-Inch Touch Screen Backup Camera Mirror Dash Cam 1080P Front and Rear Dual Lens with Waterproof Rearview Reversing Camera(Free 16GB SD Card) https://www.amazon.com/dp/B07H77GYR4/ref=cm_sw_r_cp_apap_jh4wL6WVMNvmj
I am very happy with this product but the first one I tried was lousy.
Individual cameras can be 4 or 5 conductor connections. If camera is mounted on the back door then you need to consider the ability,of,the door to open. I mounted my camera inside the RV, so it is fixed in position and looks out the back window.