DH Bahnson
Porter History and Timeline for Porter House
49 Maryland Avenue, Phinney's Point, MA
The photo above is believed to have been taken in 1903 when the dwelling was used as a boat house on what was known at the time as "Curry Point", since much of the property was owned by Mary A. Curry.  Several land plot diagrams exist from that time frame (click to enlarge):
Shown on this map, my great-grandfather Alton B. Hastings owned two plots of land on Maryland Avenue, but much of the land was still owned by Mary Curry at that time.

Records indicate that he had purchased lot #3 in 1903, so this map is likely from some time between 1903 and 1910.
In 1910, Alton Hastings acquired lot number 8  (along with lots 6, 7, 18, 19, 20, 21)  from Mary Curry.  (Recorded in Book 302, Page 45 at the Barnstable County Registry of Deeds.)

Lot #8 included the boat house which was subsequently converted to a recreational gathering place, apparently with a pool table.   It was later converted to summer cottage and the stone fireplace was built by Alton Hastings during that conversion.

Notice that there is a deeded right of way, which still exists, around the southwest portion of the point.
Lot #8, which included the original boat house was then used as a site for a home for Alton's son, Alton B. Hastings, Jr., and is currently owned by the Keeler family.

Although there is no corresponding land plot for the new home, review of the deed records shows the following transfers:

1933 - Alton B. Hastings, Jr. to Brockton Savings Bank
1933 - Brockton Savings Bank to George Jenkins
1949 - George Jenkins to Margaret Nelson
1961 - Margarat Nelso to Robert and Jeanne Scannel
1966 - Jeanne Scannell to George and Helen Keeler

Alton B. Hastings
Alice Hastings Porter
     During his lifetime, Alton Hastings gifted the homes on Phinney's Point to his children, with the house on 49 Maryland Avenue going to his daughter Alice Hastings (Porter).  All of that the property except for 49 Maryland Avenue has since been sold.  Since his acquisition of the lots in 1910 the following transfers for the current Porter House are recorded in the Barnstable County Registry of Deeds and in Probate Court in Plymouth:

1921 - Property was deeded to Clinton Porter, Jr., husband of Alice Hastings Porter
1955 - Alice Hastings Porter died without a will.  Frank J. Ryder, Jr. was granted administrator rights to her estate, and the property was transferred to Alice's four daughters.
1979 - Alice's four daughters, Mary Buddington, Jane Ryder, Louise Bahnson, and Suzanne Wilkins deeded the property to the Porter Family Trust
1992 - The four sisters appointed their children (Barbara Buddington Angle, Suzy Ryder Herriman, Dave Bahnson, and Wayne Wilkins) as successor trustees of the Trust
2018 - The Porter Famly LLC was formed and named as beneficiary of the Porter Family Trust  (Book 3044, Page 236)  Suzy Herriman tranfered her interest to the LLC.