I've noticed that you can tell a lot about a Fallout game by the first town you come across (after the intro area)

In Fallout 2, there's Klamath. Klamath oozes personality with every character you meet. It has every type of quest you'll find, and gives you a strong impression of the social commentary for the game (with how you meet Sulik). It has impossible fights that you can stumble into, and in a word is fun but not fair.

In Fallout 3 there's Megaton. Megaton has interesting side stories that you barely interact with (i.e. Simms and Moriarty's dispute, the slow expansion of a town built originally by religious zealots into a commercial hub), and a few simple quests. The combat area nearby (Springvale) also seems to have stories that you aren't a part of, and none of the combat is terribly difficult, and all quests (but Wasteland Survival Guide) can be done quickly at any level. Finally, there's the game's morality be a saviour, or a monster, no middle ground.

In New Vegas, there's Primm (with the NCR Outpost being a secondary part of the location). Simple combat, some of which can be skipped, a story that revolves around you making the important decision for the people living there instead of them making their own damn decisions, and a traditional Western theme of Civilization vs. Frontier.

In Fallout 4 there's Concord. You get to here about a sad story in the past, introduction to the settlement mechanic at the end, and POWER ARMOR MINIGUN, giving you the strongest things you'll see in the game, but with terrible upgrades to show you the importance of the upgrade system.

Hbomberguy talked about something called play conditioning in his video about Bloodbourne, and I find the way the Fallout games condition you to think about each of them through their first town fascinating.

Concord isn't so much a town as a ruin with some refugees passing through. I'm not sure it should be included. I mean, in getting to Klamath, it's possible the character passed through several ruined areas and we just didn't see it because of the way long-distance travel worked on the map. Random encounters in fallout 2 sometimes imply that there are ruins all around that are just not important.

These kinds of games are all about making decisions for people, now that I think of it. Primm being a good example of how their input doesn't exist or doesn't matter.

Things went a little more slow in the older games. That's why Goodsprings, Shady Sands and others were slower and had less loot, but at the same time helped build the world up.

It's Bethesda, they don't do pacing. At all. They like to put what should be late game content as early as possible. It's one of their weirdest quirks that flies in the face of almost all computer game thinking.

I would argue that the first town that you encounter in Fallout 4 is Diamond City since Concord is more of a crossroad where people meet(or get ambushed) and nobody lives there except for a deathclaw, some roaches and a mirelurk.

But I agree that most of the Fallout Games do tend to do play conditioning well. An example would be the town of Goodsprings. You act on requests given by NPCs and learn that there are consequences for it. This is prevalent throughout New Vegas that it conditions you to think that you cannot just help/deceive/kill a guy and expect that there would be no consequence.

Or that minutemen quest where you act on Garvey and his posse needing help and in the process learn about the new power armor, crafting and settlement game mechanics.

I don't really think that towns exclusively conditions players in fallout games but rather the first interaction with what the game has to offer.

Concord was a town, pre-war. It's really not anymore, as it doesn't have even a single resident merchant. I'm not totally even sure the raiders were permanent residents. SO yeah, I'd go with Diamond city, assuming you followed the quest line and didn't wander randomly.

I argued that they don't do "conditioning" well at all. The tutorial uses what would have normally been late game content. Bethesda loves that -- late game content in the beginning. By the time you're high level, you have so much power armor, or have killed so many dragons, or have shut so many oblivion gates, that they're tedious and unexceptional instead of "wow! grand finale!" that they could have been.