Hello,
I am planning to stay in Northern Wales mid-April 2014, and would like to visit the Snowdonia Park by foot. I will be travelling solo and without a car, depending on public transportation, so I'll be somewhat restricted.
I will be staying next to Manchester Airport on my first and last nights.

I would like to base myself in one main place in Snowdonia during my stay, and travel via buses to various spots where I can take nice walks.
I would really like to stay in a small village, but perhaps if I will be alone with no car, that's not a good idea.

It would be great to get some recommendations on planning my trip. Thanks!

Snowdonia isn't as good for carless travel as its puffery pretends. It's good for getting to by bus, but its tourism grew on the back of daytrips from Liverpool and Manchester, of which it's a wild rural suburb. So it's not that easy to do what you want.

You need to start off with bus maps of the area, and its immediate neighbour. A map of the Gwynedd county bus service is at http://www.gwynedd.gov.uk/gwy_amserl...wasanaeth=CGC2, and the corresponding timetable, in English, is at http://www.gwynedd.gov.uk/gwy_amserl...088&language=1.

The Snowdon Sherpa can help a lot (http://www.gwynedd.gov.uk/gwy_doc.as...uage=1&p=1&c=1)

But it also helps to have the same information about services in the next door Borough of Conway (http://www.conwy.gov.uk/upload/publi...metabler3b.pdf)

Bangor is the obvious place to be centred, but doesn't meet your "small village" criterion, and some places on the Gwynedd map that look to have a number of bus connections are simply vile (Pwllheli, for example). Without wishing to be unnecessarily offensive to the Welsh, being carless in a small Welsh village on a wet Wednesday when you've done both the available walks is most people's definition of complete hell.

Work out the walking you'd like to do: there's lots of free walk ijnformation at http://www.visitsnowdonia.info/travel-12.aspx and http://www.visitsnowdonia.info/Conte...13%20Final.pdf

Then choose a centre: I'd go for Caernarvon, as it's called in English, rather than Bangor if it suits your walks. If anyone recommends anywhere smaller, treble-check its accessibility to other places, whether it's got anywhere to eat and whether the pub's still open before being seduced by tales of the beautiful views. NO view in Wales is worth having to stare at it through relentless rain for three days.

Caernarvon would be my choice too. You really don't want to be an ANY small village car-less. There are some buses of course. But they aren't at all frequent. Being in a city like Caernarvon means lots more flexibility - plus food/drink options, plus a great castle of its own. And if the weather turns truly vile so that you shouldn't be out on the mountains there are things to keep you busy.

You need to decide what type of small village you want. Neither Bangor(a city albeit a small one)nor Caernarfon(a town with no aspirations at all to being a city) will tick your boxes.
However before making recommendations which will not help perhaps you can tell us whether you envisage your walking to include mountain walking (that is up ...and down) or generally flat.

If it does rain a lot head for Anglesey. It is often drier there, and the walking is good, (and a lot more level, so less dangerous in bad weather) too.