It is a difficult spot to have a neighbor like this.

If you feel you need to be available to her, I think you should
practice your boundaries.

1) You cannot change her..don't ever criticize her, or correct her. Narcissists love flattery, and compliments. If you stay on this level, you will be safer.

2) This relationship is all about HER (don't expect her to consider YOU at all or very often). If she needs rides to doctors, or things similar try not to talk about YOURSELF..anything you say of a personal nature will possibly end up behind your back.
Narcissists do not keep confidences, nor are they tactful.

The senior citizen clubs are a good idea. In my family they worked for a while.
But eventually the other members get the Narcissist's number and begin to avoid. It is not unusual that N's move around alot. If your neighbor shows this
inclination, I would encourage it. She has probably left many situations this way, moving into new neighborhoods.

3) Narcissists are good manipulators. They are also good actors. Don't let her "fool" you. They typically do not form normal intimate relationships..their capacity for intimacy is limited or nonexistant.

4) The best match for a friend or intimate is a person who was raised by narcissistic parents. These people understand the dynamic naturally, and can put up with things that others consider abusive.

The alcohol problem and the gun problem are very worrisome to me. So PLEASE do be careful!
( my husband's aunt became assaultive as she aged...she attacked people)

5) Try not to express affection for her verbally. Once a person does this, the
Narcissist often becomes worse/abusive and begins taking advantage. Keep everything very civil and neighborly.

I think it can be done. I think if you have the ENERGY you can do it. Just don't let the hurtful things or let your expectations disappoint you. You deal with patients after all, so you know how it can be. Keep her in that category.
And GOOD luck. You can always email me, if you need someone to talk to.