Our booking engine at tickets.railforums.co.uk (powered by TrainSplit) helps support the running of the forum with every ticket purchase! Find out more and ask any questions/give us feedback in this thread!
Royston is not needed, because it's covered on Cambridge lower part screen 5.
You will not be able to chain Peterborough and Cambridge directly, because there's a few boxes between.
Pitty Slough New is a IECC, otherwise it could be Peterborough+Cambridge+King's Cross+NLL+(Slough New)+(Reading)+Westbury+Didcot+Swindon+Bristol+Exeter.