Portable Heater Recommendations? (CO Detector Issues?)

We use non-serviced State Park sites for virtually all of our RV use. For the last 8 years with 3 different motorhomes we have used a Mr Heater Buddy Heater for our primary heat source. We go RVing year around so many times it is on 24/7 for a week or two at a time. We follow the safety instructions provided with the heater and with CO detectors we test regularly we have never had a alarm.

Jim