Need advice regarding valuating water view rentals

[Ruthy Taylor]

I'm looking into a 7 unit property with 5 small 1b/1b units and two 2b/1 bath units. They are small...the one beds are 646 sq ft, one of the 2beds is 800 and the other 892 sq ft. There are waterviews from the units (however I don't know if the views are available in each unit--the MLS description is nonexistant and there are no interior photos). I've driven around the property, it's in a great area (A) and the condition looks pretty good (built in 1946---surrounded by homes built in the 1900's.).

The plan is to turn these into higher end rentals, and perhaps airbnb 1-2 of the units.  The one bedrooms rent at $750--there are NO COMPS.  The only waterviews you can find in this area are from large single family homes....I'm having a hard time figuring out what a 646 sq ft high end water view rental could command in rents--in general I'm having a hard time valuating this deal and if there is someone with some experience with view properties I'd appreciate any help!  

(I've purchased duplexes and triplexes and a vacation rental...this would be my first venture into commercial--any tips would be appreciated!)