Infrastructure (eg water, sewer, electrical supply to the house) should be the landowners' responsibility. 

Without solid knowledge on this subject, you can easily end up in hot water. 

We like the short-term rental idea because we could stay at the property ourselves when we want - summer break, spring/winter breaks, etc.Our budget will be right around $1M or less ideally, and we would like a short distance to the ocean.How likely is it that we could find a property as described above and have it cover or come close to covering the mortgage? 

The interior was made up of high efficiency HVAC systems, contemporary lighting, and electric water heaters.

The yard looked like trash, plumbing stack leaks and multiple water heater leaks.

I would also look at the availability of public water and public sewer, if not at the site how far away are those services.

I assume you are mostly looking for leaks and water damage?

water heater? 

(normally recommended, especially if you are a landlord)- Water Backup: For water damage due to the backup of Sewers or Drains.- Personal Articles: Coverage for belongings that have a special or collectors valuesuch as Jewelry, Furs, Fine Arts, Collectibles, etc...Your age should not be a factor on the pricing but, depending on the company these other factors may get you credits:- Insurance Score (company pulls certain info out of your credit report).

If she is willing to pay a pet fee each month and is a decent tenant otherwise why give notice in the spring?