I was just doing some reading on another (big, popular) RV forum. A member did measurements of the temps in his 6 cu ft Dometic in his truck camper last May, and showed a column of figures. Despite ambient temps exceeding 100*, his fridge was staying around 40* on shore power (parked with fridge side shaded) and rising to 55* on LP. But his freezer was staying at zero or below, so he figured he could just freeze some water overnight and move the ice to the fridge in the morning. A 50*-60* difference between fridge and ambient sounded really impressive, though.
But then he bought a different (preowned) camper. Same model of 6 cu ft Dometic, but different camper. And in August he reported that his new-to-him fridge was only in the mid 50s while driving in mild (70s) weather!
My take: I think if construction and installation of an absorption fridge is just right, and if the unit is working optimally within its design (not low on ammonia, etc, etc), it is possible to achieve excellent cooling. But the odds of getting everything just perfect... and keeping it that way... are downright slim! Using an absorption refrigerator in an RV during hot weather might be a bit like playing roulette, with food instead of colored chips.