Hello future Cambridge person!
Cherry Hinton is probably best value for money, especially if you are working at the train station - it's not far at all. It has one of the best bus services as well, although the buses are slowly getting worse throughout the area - I would not choose somewhere to live that is ONLY accessible by bus, especially a village. Some quite adjacent villages have no bus services at all (Harston, which is on your list, being one of them).
Chesterton is a nice bit of Cambridge which is not too studenty. When I lived there I paid 250 quid a month for a room in a house share which I guess will have gone up SOMEWHAT. Personally I would not mind living in some bits of Arbury/Kings Hedges, there is more space there, if you're in a house you'll probably get a garden, and it's only relatively dodgy, compared to the rest of Cambridge (Moss Side it ain't). Orchard Park is new build and quite poky little apartments but might be a bit cheaper. It would be fine if you were only there 4 nights a week. There are NO facilities up there though so if you want a shop or a local pub, look elsewhere.
I work in Histon, it's a half hour ride on a sit-up-and-beg style bike - I don't get sweaty (I do the reverse ride, from the station). There is also a bus which is frequent, but can be slow (it takes longer than cycling). Histon is a nice village, with a lot going on, but priced accordingly. Trumpington is probably also expensive, but now has an EXCELLENT cycle and bus track which is totally offroad and takes you right to the station. There is loads of new building going on up there which is aimed at the big new tech company employees, so a lot of people probably in the same boat as you will be living there.
Anywhere in Cambridge I would bring the bike indoors if at all possible. Rates of theft are HIGH, and the police don't want to know. There is the Cycle Point at the station for parking indoors - whether it is 'secure' or not depends on whether you think having CCTV that no one monitors is a good deterrent for crime, but it's better than parking outside in the rain. I park on the second floor based on my belief that scrotes are lazy and won't want to climb the stairs!