I'm "Accepted" among the NCR, and I tried to get in the front door of the plant, but Haggerty won't let me in, and I've no options to talk her out of it. Before I became "Accepted", I did step forward towards the door and get a warning, so is this why?

I rather not use the locked door, for... character trait reasons. >_>

Look on the wall to the right

(Oh, a side clarification, traits as in character personality and such. Roleplay junk.)

Isn't that the locked door?

Yes but you can pick it and enter at your leisure. No-one inside will care

Edit: Though I wouldn't recommend going OUT the front door. Just a precaution

Did you talk to Lieutenant Haggerty and pass the speech/science check?

Are the speech and science checks the only way to get her to let you in? Reputation does nothing?

She should let you in with Idolized if you can't pass the other checks.