Line of sight is the conservative and baseline propagation mode. You can
more or less rely on that when the terrain is flat. There are Mathematical
models that are somewhat predictive. Variations in elevation play a great
part and living closer to water usually means you are lower in elevation.
When there are variations in elevation, things that reflect and things that
block the signal add to the complexity and the calculations usually go out
the window. Area knowledge of the various sites and their odd coverage
areas might more resemble an inkblot test. You may find an online coverage
map for Empire State Building as it is a major radio and TV site. This
might give you an idea:
http://www.tvfool.com/

For the VHF channels, weather also plays a great part. Thermal inversions
that result in a cold/warm layer of air can act as a reflector, often
doubling the range. I routinely talk to people 100+ miles away this way in
the Summer months, but by Winter, the path is gone and can't even hear them
anymore. You may have an advantage if your path goes over the water,
otherwise it will hurt to be lower in elevation.