If you're not a stealth build and you have/want the Robotics Expert perk and don't mind ruining a vendor, I have something for you.

Hack KLE0 and use the "Command" function. This will set her as your Robotic follower. She can now be killed only by you and she's a frikkin' Assaultron follower. She's also a merchant. See where I'm going with this? An immortal Assaultron merchant follower. Needless to say, she comes in handy.

You can also hack the Combat Sentry Bot at the Robotics Scrap Yard at the top of the map, he's kind of a total beast.

The only issue with the hacked robotic followers is that they don't fast travel with you.

Yes, robots do fastravel with you. Hack and then use "command". Go to pip-boy and choose a destination with a bed (important). Fasttravel and sleep one or two hours and look.... who is there..... your precious Be sure youre alone, because any hostile robots will attack anyone who are nearby except any companion your bring with you. Only way to make hostile robots none violent per today, either use mod or use of game commands. Remove all factions and addfac player faction and MM will do. Remember that some robots have certain spawn location(s) and if youre nearby such spots, they will leave the new destination and rather spawn at these locations?.

Sentry bots are more easy to handle than Assaultrons. I have few named hireble traders in Sanctuary and these are not member of player faction or MM, so Assaultrons will attack these on sight. Only way to add hireable traders to players faction and/or MM. Some farms do have certain settlers not members of any factions so these are free target. You need to add these as well. Either by mod or game commands per today.

Cheers,

-Klevs

The bots have to walk to wherever the SS fast travel.

If you're on PC, a nice non-hostile robot to use is Sarge. After you complete Old Guns, his shell remains where you destroyed him, and if you resurrect him he will no longer be hostile (since he isn't, just that Old Guns has a flag which makes him so after he malfunctions when activating). Always nice to have a named robot following you, and Sentry Bots are vicious. He doesn't look like he can follow you out of the basemant since he can't climb stairs, but he does appear on the outside when you go out.

Other than KLE-0 and the other sentry mentioned by the OP, other popular robots to use are those outside the Cabot house. If you can get to the racing robots before the announcer turns them hostile they may stay green, although I've never tried it.

The racing robots did not work so well for me. I had Curie with me and without any warning, she begin to shoot at hostiles human npcs. Everything went havoc. There are some bots at that location not part of the racing team. You can hack these. I find most bots not very usefull, sentry bots too huge and clumsy. They are easy target for hostile missiles. Assaultrons can use stairs etc... they are far better, but they do attack everyone else. If they spot BoS' Vertibirds, they will follow the thing and run away. They are difficult to follow since their speed > players (if you carry alot of items). Other robots, they don't have much damage resist and easy killed except Colonel Gutsy. That one is tricky.

Cheers,

-Klevs