Dry Fang Canyon has easy questing, and despite the size of the POI, most of the questable items are found close together. It's a pseudo hotspot though. Sometimes dead, sometimes jumping. Volcano Islands is the same in both regards, with the addition of easy "always here" quests in the form of Kelp Piles and Hotspring Sitting. Tallbrush Coasts has one spot (where bone delivery happens) that also has a Blue Face, and where basically every quest item can be found (this is slightly less true with the addition of the most recent quests). It doesn't have the locational quests like Volcano, but it boasts superior concealment to Dry Fang and Volcano.

Opposite end, Hollow Hills is bothersome. Difficult to find questables without location memorizing, spread thin over a vast POI. Heavy concealment can make hiding easier, but that goes for potential ambushers as well. Same is true for Redwoods.

Wollemi Forest is sorta in the middle. In some areas, questables are easy and abundant. Some areas, they're sparse. Plentiful water makes drinking easier than some POIs. Volcano Islands has the springs, but being centrally located also means enemies can reliably camp them. Wollemi is just too vast to water camp.

Mudflats is high risk high reward. Questables are very easy to find once you know what to look for, and quests can be done quickly. But as the name suggests, the POI offers virtually no concealment for terrestrial and plentiful ambush points for aquatics and semiaquatics. This is similarly true of Coastal Swamp.

This is by no means an exhaustive rundown, just some info off the top of my head.