For your 2021 Heartland Trail Runner Travel Trailer I recommend the Furrion Vision S Wireless RV Observation Camera System Item # FCE48TASL-05. This kit comes with the the rear camera, two side cameras, and a 7" LCD color monitor. All cameras have LED lights for visibility at night. The rear camera has a built-in microphone and the system has built in motion detection. The system is a wireless system and does not require a wire connection from cameras to the monitor. Each camera simply... view full answer...