Tails Noir

At the beginning of act 4 you'll wake up in a tent under a bridge. The goal is to never interact with any other NPC besides Larry and another story character until the end of the second night under the bridge. I don't believe any of the dialog choices are important for Larry and the other story character, but I was going to for the true connection achievement so I was making those choices. YMMV.

To do this, after talking to Larry for the first time in the morning of day one exit the tent. Go all the way to the left and interact with the tree to get some firewood. You'll fall asleep under the tree and talk to the other story character. After waking up go back to the right and talk to Larry next to the firepit to end day one.

Another chat with the other story character then after waking up on day 2 talk to Larry again and exit the tent. Now, go all the way to the right and interact with "Sit at the edge."

Select in order:
"Sit, and dip your feet in the water."
"Drift away."

You should see the time of day change slightly. Next run all the way to the left and interact with "Sit alone."

Select in order:
"I am tree. Reaching towards the sun."
"If I could just feel like this...a few more times..."
"Become one with the forest."

There doesn't seem to be a change in the time of day here. Now go all the way back to the tent on the right, go back inside, and take a nap. Here is where, it seems, most people unlock the achievement. However, if you're like me, this never worked.

So, if the achievement is still locked, exit the tent. And now we're going to do something that should conceivably void the achievement, but didn't for me. To the left of the tent, past the family of mice sitting down, is the NPC Casey and we're going to chat with them. I have no idea what options are the "correct" ones, if any, so I'll just list off what I chose.

Select in order:
"I'm working on it."
"All I ever wanted to do was help people."
"Thanks. Are you doing well today?"
"What makes you fell tired?"
"That must be difficult. I'm sorry."
"How did you end up here?"
"How did that happen?"
"I'm very happy to hear that."
"I believe you. If you feel it, it's real."
"I'm gonna take off."
"Glad to hear it. Seeya, Casey."

Next go right and talk with the Geezer.

Select in order:
"Regard the geezer patiently."
"I am friend."
"Reach out to pet the geezer."
"Sit with the geezer and notice the world together."

Notice another time of day change here. Now go back and talk to Casey again.

Select in order:
"I had a Casey craving."
"That offer to hang out still open?"
"Awesome."

And here, for me, is where the achievement unlocked at the cutscene of Howard sitting at the edge of the pier on the right side. I have no earthly idea why some people have to do this extra bit while others can just do everything up until taking the nap in the tent. This game's achievements are notoriously difficult via their obtuseness so there's very little to go on in-game to know you did or did not do something correctly.

If you'd prefer a visual guide, I followed this one exactly so shoutouts to The Welsh Hunter on youtube: