A few disconnected thoughts -
Presume you're aware that property sites like 'rightmove' mean you can search by area / near to particular stations etc. Personally, I'd be inclined to rent initially if I was moving to an area I didn't know at all rather than rush in to buying.
Nobody can really generalise about a particular postcode / area of London - it's mostly too much of a patchwork - one street may be completely different to the next.
Anywhere that's off the Underground (and is served by other railways - either the London Overground or the National Rail network) is usually a bit less expensive for house prices / rent. Many of the NR / Overground lines run at least every 15 minutes or better at peak times.
There is a journey planner on TfL's website
here - you can plan journey by street name or postcode without knowing what the nearest station / bus stop is. The only snag is the more central you are, the more options it will suggest.
Bear in mind that the London Underground 'map' is a diagram not a real map, some places that look quite far apart aren't really, and there are a few journeys that look like you have to go a couple of stations one way, then change and go a couple of stations another way, it's really quicker to walk.
Transport in London is not deregulated like in the rest of England, so buses are part of TfL as well - Oyster Card / Travelcard gets you on any train / underground / bus within London so you don't have to think about which bus operator it is and which ticket you can / can't use.
Oyster and Travelcard also do things like the Docklands Light Railway and Croydon tram although these may not bother you. (They don't cover commuter coaches from outside London, sightseeing tour buses, and the Paddington - Heathrow link.)
Most London bus routes are quite frequent, and operate quite late into the evening - but journey times are slow especially during peak hours because there's so much traffic on the road. There is also a fairly comprehensive network of night buses / 24 hour bus routes - the railways and Underground generally shut down somewhere around midnight. (some bits of the underground may eventually run all night on Friday and Saturday nights but that was all supposed to start some time last year and it hasn't yet)
There are about 500 bus routes in London, so if you try to digest the entire network at once, it can be a bit daunting. They do 'spider maps' showing all the routes from particular locations - you can see these on the web
here and they are shown at a lot of bus stops as well. All bus stops show info about the routes that call there and where they go along the route.
Camden is fairly well connected - as others have said not far from Kings Cross / St Pancras / Euston and of course is on the northern line (although this is very busy at peak hours - it can for example be difficult even to get on a northbound train at the Clapham stations during the peak hours.) It's also on the London Overground line that runs from Richmond (SW London) to Stratford (E London) - and any journey that avoids going in to zone 1 (the central bit) will be cheaper than a journey that does.
If you are in Camden then you can get there easily as there are loads of Tubes, Buses, Rail, etc that get you there. Depending on where in Camden you can use Kings X, Euston, St Pancras main line stations, plus Northern, Piccadily, Victoria, Circle, Metropolitan, Hammersmith and city, and the Overground to get in. Camden is expensive to rent in though, but exciting to live in I'd guess. It is very green, Hampstead Heath is a great green space to the North of the borough.
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. As long as you've a paper copy (as 
