My thoughts were generally that "Freedom Fighting" was something of a strategy, or a wider goal, while "Terrorism" was a tactic. But terrorism isn't exactly my lane, so I would like to ask the same question to the wider community here at SWC.

Is one man's terrorist really another man's freedom fighter?

What are the differences?
Freedom fighting implies an objective or goal, not a strategy. Terrorism as you pointed out is a tactic. Freedom fighters and dictators can employ terrorism as a tactic to pursue goals, so it is an equal opportunity tactic.

The FBI definition of terrorism is almost comical, since its scope is much greater than most would assume is terrorism. Almost any insurgent, state actor, that has waging a conflict with the U.S. could be classified a terrorist.

The FBI defines terrorism as “the unlawful use of force or violence against persons or property to intimidate or coerce a government, the civilian population, or any segment thereof in furtherance of political or social objectives.” The FBI further classifies terrorism as either domestic or international, depending on the origin, base, and objectives of the terrorist organization.
More appropriate in my view from the CIA since it focuses on non-combatant targets. I don't think an attack by irregulars against military targets is terrorism, but rather an irregular attack. When they attack civilians that is another matter.

A: The Intelligence Community is guided by the definition of terrorism contained in Title 22 of the US Code, Section 2656f(d):
•The term "terrorism" means premeditated, politically motivated violence perpetrated against noncombatant targets by subnational groups or clandestine agents.
•The term “international terrorism” means terrorism involving the territory or the citizens of more than one country.
•The term “terrorist group” means any group that practices, or has significant subgroups that practice, international terrorism.
Freedom fighter is another over used term to gain legitimacy, but as we all know not every group that claims to be freedom fighter has anything resembling freedom as its goal, unless they mean freedom to pursue their goals.