I went to Cesis from Riga by bus, about 2 1/2 hours each way. Cesis has the ruins of a splendid medieval castle - see the reviews and photos here on Trip Advisor. The ruins are compact, easily seen and not overrun by tourists.
In my opinion you should consider Sigulda. There you can check out Sigulda castle, and for example do bobsleigh - really fun!.
Sigulda is aprox 50 km away from Riga, and you can get there by train or bus.
I would even consider going to Daugavpils in winter. First, it is quite far, approx.230 km and the train or bus ride takes quite a long time. Second, the main attraction of Latgale region, where Daugavpils is situated, is its pure nature, lakes, forests, rivers, but in winter the majority of them is not accessible.
I would advice Ventspils. But also, it is a summer destination and again not so close.
Cesus and Sigulda are the best options.
From the airport to the center a taxi will cost you aprox. 8-9 LVL (10 english pounds). Bus is of course cheaper:
Gauja National Park is open every day. Here you can find more information about when the visitor center is open etc:
About Gauja National Park - it is "open" all the time, because it's huge territory that is under protection of law, including various nature values. But if you want to see something, you have quite limited choice when using public transportation - many objects are situated in places accessible only by car. From visitor centers mentioned in previous post only Gūtmaņa cave (in Sigulda) is close enough to be reached on foot; Līgatne Nature Trails can be option too, but public transportation is less convenient to get there. So, if you plan to use bus or train, choose Sigulda or Cēsis; look through previous posts about these locations, there are plenty of suggestions what to see and do there.
Bus, shuttle or taxi from airport:
-:- Message from TripAdvisor staff -:-
This topic has been closed to new posts due to inactivity. We hope you'll join the conversation by posting to an open topic or starting a new one.
To review the TripAdvisor Forums Posting Guidelines, please follow this link: http://www.tripadvisor.com/pages/forums_posting_guidelines.html
We remove posts that do not follow our posting guidelines, and we reserve the right to remove any post for any reason.