More thoughts on the "choose one" class features. I originally vented some frustration at these being siloed instead of in a general pool like the Adept's Focus Features, but it turns out my choices would be pretty straightforward at most levels.
Trained Accuracy, 2nd level
Interesting tradeoff between Accuracy Bonus's limited uses and potential to get a really devastating hit, vs. Accuracy Reseve's steady but smaller bonus if you don't move, assuming it doesn't accumulate (which would be crazy). If you only get to choose one (as implied by formatting), I'd definitely go for Accuracy Bonus so I can pull off that crazy-hard shot. If you get both, they can stack, and that's pretty hot.
Wilderness Mystique, 4th level
Kindred Spirit seems clearly more powerful to me than the other two. Answering Silence is thematic as heck, but you're already the Nature/Survival expert, so why wouldn't you just do the check instead of helping an ally? Group challenges, I guess. As for Fearsome Mysticism, intimidating non-spellcasters seems very situational. But a boost to detecting hidden/invisible creatures seems to be useful much more often, so Kindred Spirit is the one I would take.
Wilderness Lore, 12th level
I really feel I (or anyone) could just work out with a DM how to do traps without having a class feature like Big Game Traps, so I would probably take Waste Not just for the extra income.

The main benefit of Big Game Traps I feel is truly distinctive—that you can do it in 10 minutes—I don't find compelling enough.
Guarded Post, 13th level
Defensive Marksman is going to come up often. Hunter's Blind is cool and thematic, but with its proviso that anybody, even another ranger with the feature, will ruin your blind, I'd give it a pass. I guess, since it counts as a haven, you could go on an extended scouting/stakeout mission away from your party, but again, how common will that be?
Tactical Advantage, 14th level
This is an even pairing, I think. Covered Shot will often be useful for combat, and Nature's Shadow for scouting. If I didn't have another way of gaining an expertise die on Stealth checks, I'd go for Covered Shot, otherwise it would depend on the type of ranger I'm making.
Survivalcraft, 16th level
Under the Stars reduces your own time for a long rest, but you're in a party, so I still have some trouble seeing the real benefit here. Then again, there are other ranger abilities that require some time, so this could help there. Woodlore seems pretty minor for a 16th level feature, but it could be an ability that changes a desperate situation into a survivable one. You can just make a fire in your hand without any fuel! And when the 10 minutes is up, you just make a new one, again without any fuel (granted, it does cost an action).
Flora and Fauna, 18th level
For me it's no contest. Beastly Attack offers 1 purely mechanical benefit (powerful as additional attacks are) to High Ground's 4 thematic ones (including a boost to base movement). I find the 5E pet action economy just obtrusively gamist, so I'm not that interested in features that dance around it.
I also don't find the A5E Beastmaster subclass that compelling (some of its features are notably weaker than the O5E's Beast Master), but I will point out that it does have
two friendly beasts by the time it gets this feature. And, if you can accumulate a mob of friendly beasts through other means (those other means probably won't be via a 2-level multiclass dip), you could get a lot of extra attacks each round.
Nature's Scion, 20th level
A5E's non-magical ranger still lives in a magical world, and so the capstone feature is at the very least mystical. Elemental Mastery gets you a 1-hour elemental pet, and Summon Stampede, well, delivers on what the name promises for 1 minute (fans of Avatar, rejoice). If you want a servant to do more than just cause random damage and status effects for one encounter, Elemental Mastery is the choice for you. (The pet elemental also gets a couple additional actions—Engulf and Guard Life—which could be useful.) But on the face of it, in terms of sheer effect on the battlefield, Summon Stampede is downright insane. You need to have a large number of beasts nearby for it to be usable, of course, but even in a dungeon or town you'll be able to at least call on Swarming Pests every other round.