I'll jump in here with my question(s).

Arriving into BOS on the 27th Oct and heading down to Falmouth on the 28th, flying back out of BOS on the 31st at 6am.
My options are to either hire a car for £87 (Fri morning to Sun evening) or catch the Peter Pan bus for around $57 / £47.

Both seem to take around 1h20-1h30.

Got plans in the Falmouth area with the half and full marathons over the weekend.

If I take the bus, the last bus on the Sunday seems to be just before 6pm and then I can overnight in Boston before my flight.
If I drive, I can either do the same thing, but leave when I want or just leave at say 2am or so back to BOS on the Monday morning.

Secondly, do I actually need a car for a weekend in Falmouth? Not sure how much there is to see and if anything major is too far out or if there's public transport if need be.