Mike,
Amelia can be viewed from a distance (1/2 mile) from Atlantic Ave about 1/2 mile between downtown Fernandina and the beach. It's supposed to be opened up for public visitation later this year.

Mayport can be seen through the fence from the end of Palmer or Broad Street. Both streets are very close to the ferry landing. I've got a better deal for you: if you can tell me when you'll be in the Jacksonville area, I'll be glad to meet you somewhere near Mayport (at the Ferry Landing?) or anywhere else and get you aboard the Naval Station for an up close & personal view of the light.
Let me know.
Stan