Having spent the last 5 years in the hot sun in Mississippi and Georgia in our travel trailer the direction that you park your trailer will have a big impact on how well your A/C cools. We spent a year parked broadside to the evening sun without shade near Jackson, MS where that summer the temperature reached over 100 degrees for something like 35 days in a row and the 15K A/C unit struggled to get the temperature in the low 80s.
After that we tried to make sure we were parked with one end or the other of the trailer aimed toward the afternoon sun not broadside. It was the difference between night and day. In 100 degree days parked with the end toward the afternoon sun the unit didn't struggle at all to keep it cool inside and would actually cut off time to time.
Of course parking in the shade will keep you cool but I'd rather fight the heat as tree sap on my trailer anyday. We tried that once and once was enough. Pine tar is nearly impossible to get off.