Is it possible for an Oyster travelcard to have arbitrary start/finish
dates, or are they limited to one week or one calendar month? And if
they can, can you buy them at ticket machines in NR stations?

--
David Cantrell | semi-evolved ape-thing

"The whole aim of practical politics is to keep the populace alarmed
(and hence clamorous to be led to safety) by menacing it with an
endless series of hobgoblins, all of them imaginary" -- H. L. Mencken