The main transport hub in Karkonosze is Jelenia Góra town. Buses and trains from various places in Poland run here. Jelenia Góra has a good connection to bigger city - Wroclaw. From Wroclaw to Jelenia are some buses a day. From Jelenia Góra You can easily get a bus to the mountain towns: Szklarska Poręba and Karpacz. If You have a few hours of free time, e.g. waiting for a bus, You can take a walk in the Jelenia Gora. It is one of the largest cities in the Lower Silesia region (Dolny Śląsk), the traffic is routed edging, so the city center is very calm and walkers friendly. From the railway station and bus station to the old market, there is about 15 minutes walk.
A photo gallery from Jelenia Gora:
Szklarska Poreba and Karpacz as a typical tourist towns have a well developed accommodation base. Many little hotels, guesthouses and private accommodation offer something for everyone. I don't recommend anything, because we did not use the accommodation in these destinations, we slept in mountain chalets. An interesting alternative (depending on your time and approach routes) is an accomodation in Michałowice and in the ruins of Chojnik Castle.
Below photos of hostels where we slept, ate and drank: