I have been to Kladno. It is closer to Prague Airport than from downtown Prague. Hotels in Kladno and taxi to the airport quite cheaper than it would be from downtown Prague. Kladno has about 70 thousand inhabitants. It is an industrial city (steelworks and coal mines) which has seen better times. A lot of prefabricated buildings (so called panelaks). Really nothing why American tourist would want to spend any time there. That's why I assume you won't be there as tourist. The city is about 20-30 km west to northwest of Prague. Good and frequent connection by bus also by train. If you are into WWII history go and see memorial in Lidice (village destroyed by Nazis as a reprisal for assassination of Reinhard Heydrich. Village had nothing to do with it). The village is about 10 to 15 km from Kladno. Southwest of Kladno (20 km plus minus) there is a protected natural region Krivoklatsko. Beautiful area, woods, hills, lot of hikes (get a map), castle Krivoklat. Lot of information about Kladno, Lidice etc. is on Google.