Cambridge is smaller and flatter than Oxford, and the famous view is a lawn running down to the Cam with King’s College Chapel behind it. That view is earned by walking the Backs, not by buying the first punt that calls to you from a bridge.
The rest of the city is laboratories, bicycles and a market square. Treat the chapel as the monument and the streets behind it as the place you actually spend the afternoon.
See
King’s College Chapel
The interior is the one ticket worth timing. The exterior from the Backs is free and, in late light, better.
The Backs
Walk from Clare to St John’s. Punts are a pleasure when you are not in a convoy.
Fitzwilliam Museum
Free, serious, and a relief from college courtyards. Give it an hour, not a glance.
Grantchester meadows
A flat walk or a short bus south if you want the river without the queue.