Long-term plan is to use gains from LP investment we made here in a few months.

There is demand for this type of housing, and buyer-landlords can achieve a decent return on investment with new properties while benefiting from long-term appreciation.While Worcester may not offer the vast expanses of land seen in other cities, thoughtful development and strategic investment in Build to Rent projects can meet the needs of residents and provide solid returns for investors.

I bought this property in college, renovated it while renting out the spare rooms and no use the property as a long term rental.

Would the piers alone be a turn off to investors when thinking about the long term ie. renters, or selling the property.

The short-term view is you lose money. 

So, I am allowed to do the 150’ expansion, as long as it accommodates ingress/egress.  

The long-term plan was to convert the garage to an ADU for future cash flow.I'm seeking advice from fellow investors.

Have your terms together on what type of return youre looking to get.....I would pitch this at a REIA meetup and funds....

At least in my state, I have recourse if the property is not delivered in the same condition as long as you have a solid contract in place. 

In any building that allows short term rentals, you will have a majority of the owners doing STR.