The conference package includes 3 nights accommodations, all you and eat and drink, and access to conference content + events + more.

They pay you $500 per night. 

Setting a one night stay increases visibility and we can always decline a guest request. 

Interesting, I was reading the Key Data report on Next Season's US Rental Trends and noticed they include owner nights and hold nights in their calculation.  

Given the details here I'd say no, you should take any development thoughts off the table because to do that is not something one simply learns over night, there is a lot to it. $209k is very cheap for 40 acres, so that offer could be a person interested for hunting land and nothing I'd get excited over, and I wouldn't assume it means anything other than you could sell it for $209k. 

One tenant claims people are breaking into the house and hitting her at night.

Summer is 100% occupancy at between $500-750/ night hosting groups of 6 or less.

I’ve owned one STR since 2005 that is occupied 240 nights a year and have incurred $1000 damage tops in 14 years.If you need an extra 300 bucks deposit to help you sleep at night, it could be costing you 20-30-40 times that in lost rents each year.  

We are taking a Labor Day trip and staying a couple nights in Grandy, which is on the other side of the sound from the main OBX locations (Duck, Corolla, Kitty Hawk, Nags Head, etc.).

If you downsize the bedroom to a point that buyers can't fit a king size bed with night stands, I would not do it.