Yes, it is 'festival of experimental archeology'. Click the British flag on Kernave website -> Information for visitors -> Events -> then click one of the titles. There are pictures + text. Also click the Map to get an impression about location. Connection Vilnius-Kernavė - by bus (there is an Informacija at the bus station's hall, by the right hand when you face the ticket office), and of course by car.
Text + pictures on Wikipedia:
http://en.wikipedia.org/wiki/Kernavė
not sure what do you mean by interesting landscape

, LT certainly is neither Switzerland nor Norway

.
As for LT residents, Kernave surroundings (closer to the river and the town itself) are interesting, no doubt.
Yet there are quite interesting landscapes within the city limits, here is a map of nearly whole city:
http://laikas.org/Vilnius.jpg
, and you can see some green peninsulas - that's it. Worth a visit, if the weather is good, check the map (from top-right to the bottom): Verkių mikas (Verkiai forest), Verkių parkas (Verkiai park nice overview from the hill at the edge of river valley), Valakupiai beaches by the river (local secret, only experienced foreigners aware), Antakalnis you can't see on this map, but if you buy the whole one you'll see Sapiegine (Sapiega's Estate), east of Antakalnis, it also will be marked on the map as Pavilniai Regional Park. It's not a park, but forest with genuinely impresive landscape. Next down Belmontas, one can walk from Antakalnis thru Sapiegine to Belmontas, would take an hour or so. Doable by taxi or car, but no public transport connection. Belmontas is a must in summer.
www.belmontas.lt , only in lithuanian (click lietuviskai), but pictures will tell you almost everything, though not about the landscape.
Seems pretty long post

).