Likewise, partnering with an investment-friendly title company is crucial.

My plan would be to actively manage the new property and hire a property management company to manage the first property. 

During that time many homeowners block the rest of the dates and have the new PM company create the new listing and gather bookings in.

The one thing I did find out when I had a management company manage my property a while ago is that there are people who rent properties full-time during the off-season at a greatly reduced price.   

Another way to find a property management company that knows those zip codes is to search rentals in those zip codes on Zillow or HAR and see who has many listings and see how they are presenting the property to the public with their pics and description of the properties.

I can't recommend you one company but if you search in google you will have a popup of some.

We would like to do it all legally with plans approved by the town.Any recommendations for an architect / company that can assist us with this project? 

Get data from your title company or RE agent showing average DOM (days on market) for listings in your subject property area, find out how many homes are currently for sale, pending and sold today, 6 months ago, 1 year ago, 3 years ago.

I also make sure I make my desire to buy properties known to those working in the city offices, utility companies, code enforcement officers, police officers, and others who are in positions to hear about potential properties.

We received an estimate for $8K from one plumbing company and $6K from a little guy plumber that we've worked with a lot.