Good work! The Sanborn maps are an excellent resource for stadiums of this era.
The one that shows Terrapin Park is especially good.
One interesting factoid: the Terrapins built their stadium directly across the street from the ballpark that was used by the International League's Baltimore Orioles. That stadium was, in turn, originally built for the American League Orioles and used by them during the 1901-02 seasons. After the FL disbanded, the Orioles moved across the street into the newly renamed Oriole Park, where they played until a 1944 fire destroyed the stadium. The Baltimore Elite Giants of the Negro American League played home games there as well. So if you need photographs of the stadium and find that there aren't many of the FL Terrapins, you could probably use photos of the minor-league Orioles playing at home - it's the same stadium.