Hey guys

Im, visiting the UK from Australia on the 1st of Jan for just over a month. Im staying in Royston but am going to need to catch the train up to Cambridge and back down again, Monday to Friday for four weeks (I assume in peak hour though Im not certain).

Id also like to be able to catch the train in to London on weekends, though Ill probably be driven around on some weekends by family.

So basically I was just wondering, would it be cheapest to just pick up a visitor Oyster card and simply tap on and off wherever I go? Or are there monthly rail passes that I could buy between Cambridge and Royston to save me some cash on the 20 trips back and forth that Ill be taking (and just buy paper tickets for my occasional trips into London?).

Sorry to be a hassle. I know this is a rather boring question. Im happy to run the numbers on prices and zones and what not. I was just a bit confused by all of the various rail types, and ticket types available (including conflicting information about whether monthly tickets are possible). Id also be eligible for student fares and an under-25s ticket (I swear I saw one but I cant find it now).

Thanks in advance for any information you guys could provide!