A visit to Hobson's Conduit on the corner of Lensfield Road and Trumpington street is worth doing, perhaps on the way to exploring the open areas past the backs.
The conduit spilt up water that came into the town from hills to the south. It then ran along various channels or 'runnels', some of which can still be seen at the side of the streets in the area.
More famously, his business (from which he could afford part-sponsorship of the fresh water system) was in delivering mail to London. This ran from some nearby stables.
As a side-line he also rented out horses. In an impressive piece of animal husbandry for the time (1570-1630) he would only allow someone to hire the horse nearest to the road (and thus the most rested animal).
If you wanted a horse - it was your only option. This is thus the source of the phrase 'Hobson's choice'.