We have cold winters in northern NH.

Metron and Southern Water Management are two that we've been talking to.

For Enclave, it seems that if we manage and post on Airbnb, our guests cannot use the water park/amenities. 

If the water bill is $100 a month, increase the price by 20% (or whatever you decide is fair) to compensate you for the time required to split and bill and to cover additional use when tenants squander the utility.

Don’t assume that you will have water.

What is the best overall water metering company you have found when it comes to ease of installation, reliability, and the cost of the equipment and monitoring?

Cold Called the seller.

@Marc Robinson what's the lot rent, who pays what utilities and what's the source of the water and sewer?

Cold Called the seller.

It's hard to say offer amount without knowing the rehab part since that could blow this out the water.