We purchased a second home in AZ and using it as a vacation rental when we are not in town. We aren't located inside an HOA and our rental complies with all local laws and ordinances. After we purchased the home, we learned there are a couple of other STR's in the neighborhood who have caused problems for the neighbors. The next door neighbor in particular was upset we were going to be a STR. I explained to the neighbors I understood their concerns (which was primarily parties and late night noise) and that we are not running a party house and will be enforcing rules - no loud parties, quiet hours after 10 pm, parking limited to driveway. I gave them my contact information and told them I would promptly address issues. After hosting for a few months, we decided to hire a professional short-term property manager to manage the property as we had one issue with a group who left a beer can outside the neighbor's driveway and knocked on the neighbor's door asking if they could borrow an item, which resulted in a long stream of texts where the neighbor wanted us to be sure we knew this was unacceptable.

Fast forward 6 months, we've mostly had great guests, but there have been a few inconsiderate guests who were either up late talking outside or decided to invite a few extra people over and have their visitors park on the street. The neighbor is still contacting me directly to let me know of any issues. In the spirit of trying to be a good neighbor, I've been acting as a liaison between her and the property management company. In every instance, we've responded promptly and issued a warning to the guest, and the behavior stopped. The property manager also sent out security multiple times to check on guests after this neighbor complained about an issue, which often results in nothing since there is no visible disturbance from the street. The neighbor is confrontational and has been having increasingly verbally aggressive confrontations with our guests. We've had a few offended guests in the last month contact the property management company to complain about the neighbor. I'm also starting to see bad negative reviews and concerned we're going to see more.

We had a guest this past weekend who invited a few local friends over which may have put them over occupancy by a few people. The neighbor texted to complain about the extra 4 cars parked on the street. We questioned the guests about the extra cars, but they denied they belonged to their visitors. We knew they were probably lying, but property manager sent out security anyway, but since nothing looked out of place, they decided they didn't have much choice to let it ride until it became late enough to where they were violating quiet hours. Neighbor complained they were being allowed to have a party which violated our rules. It appeared they were all in the backyard playing in the pool and grilling (I have a driveway security camera and couldn't hear any noise either). 5 minutes after the 10:00 pm quiet time began, guests were cleaning up in the yard to go inside and neighbor verbally attacked over the block fence wall letting them letting them know she was sick of vacation renters. She has texted me to tell me she is 'done' and demanded we either move to AZ and occupy the house full-time or sell it to someone who will.

I believe this next door neighbor is going to actively sabotage our future guest's experiences with this home. We will always stand by our neighbors and address any inappropriate guest behavior and I certainly understand their concern, but this one particular neighbor is confrontational and aggressive and is making unreasonable demands of our property management company and our guests. She has also begun to threaten to call the police. None of the other neighbors are particularly excited it's a vacation rental, but I have not had any other neighbor conflicts. 

I am looking for any advice on how to address things with this neighbor. While 3 or 4 of her complaints have been reasonable, the rest have been unreasonable and overblown. I've already given her contact information to contact the direct person to call security at our property management company. She is overly focused on our home and looking for a fight. I don't want every guest being hassled because they looked at her house wrong. 

We're past the point of me bringing over a bottle of wine to smooth things out. Any ideas on what we can do to protect our guests and investment?