A "couple of hours" for you in Falmouth translates to roughly 4-5 hours of road time for the driver plus the hours waiting for you. Even with "no frills" this is would be considered a full day for him. You'll need to consider that when looking for "cheap fare" with a charter driver. Truly the "cheapest price" will be with multiple route taxis, but obviously not for someone not used to the local system and who doesn't enjoy much of the day's activity to be spent on the road vs being at your destination location site.

Are you visiting local friends there? Just curious about Falmouth? When you mention staying in the area, do you mean over night or just on these day trips?