Final weapon upgrade locations?

[shadowsouled1]

Love the game! its fantastic, truly.
Now... where are those forsaken final upgrades? lol

Chel - Get to capital city, then go back to the scrapyard, talk to the guy there and he will say "bring me 3 mega scrap for the upgrade", those seemingly can appear on any map, but the upside is that if you go to a map that has one it will make a ping sound to notify you to be extra on the look out. Got this one aleady.

Robot Guy - Get to capital city, then return to silvington base, a scientist in the entryway throws a hissy fit and gives you his key, use this on a door in the room where you fought Cherk for the last time, fight boss in there and get Robo Dudes upgrade, Got that one.

Soldier Guy - Get to capital city, then return to hogtowne checkpoint, approach the iron looking doors on the northside of the map. I theorize this is where this guys final upgrade is, inside that bunker, but when you approach it he talks about it and then just says "we need to find someway to get in there.." helpful lol, cant figure this one out, though i do note an extra rail track in the far north of the mines later near greensprings that may in some way be connected? not sure, any help would be appreciated.

Penton - Ive got nothing, not even a hint of where to go for this one.

Anyone who would like to help out would be greatly appreciated!

[Neon_Phantom]

Just got Tarnstrom's upgrade.
Once you can access the boat in the Capital City sewers go to the left and then in the next area enter the bottom room. There's a computer here that will open the door at the Hogtowne checkpoint.

Is Chel's upgrade worth it? I found two really easily but I definitely don't want to recheck every area and dungeon in the whole game.

[shadowsouled1]

So far Chels is the most powerful, to the point of overkill, one of the options for it is to attack 2-6 times with basic bullets, if you max her marksmanship she will hit for around 1k damage 2-6 times in a row, wipes most fights instantly

[shadowsouled1]

so to update this, Penton's final upgrade is in the Biodome ship - forest area. I put all of this into a guide and posted it for the game, all 4 final weapons as well as the location of the Nuke schema, for people who are worried about missing them, they arent hard to find at all, I just didnt want to accidentally trip a point of no return and miss out lol

[Leogrim]

There aren't that many points of no return and usually they are temporary.
One is the outlands/desert until you get the energy cell and the other is getting to the generator in the tower.
In the city you can talk to one of the NPCs to either port down back to the Shantytown or to the city limits and from there take the bike to get where you want to be.