After I tried to go into Vault City Council without knowing it is restricted and then got killed, at the same time losing 20 superstimpak today,
I decided to make a thread like this, so no1 has to die the same stupid way as I did, if they read.
You can help too by input your own experience or give advice so that new player can avoid dying stupidly.
So first about Vault City,
If you are not a citizen of VC, do not try to go through the inner gate, you will get killed the moment you try to open it.
There is a quest to become a VC citzen, talk to the guard on the right of the inner gate, however, whatever options you choose in the chat dialog, DO NOT choose the one with "prepare to die" (I got killed by accidently clicking that option and lost 5k caps)
So even after you become a citizen of VC, you can't get into Vault City Council; you can try to open its front door, but then you will be shot by 4 mini-guns. (I am not sure if there is any quest or reputation thing that grant you access, but if you wanna try, go naked)
And I guess Vault City Council is not equal to Vault City Headquarters where you can find Lily (correct me if i am wrong)
Junktown,
When it is night time, the gate of Junktown is closed. If you try to force in, sometimes the guards will shoot you; when I say sometimes, yes, there are times they will just let you pass during the night, but you have to try you luck, or if your reputation with junktown is high enough (please comment, I read it somewhere, but not sure if it is 100% correct)
NCR,
Most new player learn it the hard way, in the inner city, you have to unequip your weapon from your active slot, or die.
Boneyard,
Boneyard is a partly guarded town, some sections of the Boneyard is not guarded, so watch out for player killers camping in those sections.