[Kraftwerk]

Shaun,
That Roberts is a time capsule don't mod it. You just need to ride it and maintain it (buy new wear items like tires & cables, sounds like you got brake pads?) Eventually, after clocking some miles, get a full carbon or aluminum or steel bike from this century with Modern geometry , 'brifters' and more gears.
Then you will have TWO bikes a classic and a future classic ..... enjoy those MA roads that is where I started riding.

PS no body needs more gears, I do some of my best riding on a single speed or a fixed gear.
(Then have lots of power on my geared bike) but it is nice to have a gear for every single slight change in speed elevation or mood.
It is just different. Smoother. Borrow a newer bike you will see.