dc metro is comparable to nyc, and much cleaner. connecting buses also good. all tourist info readily available, just visit a info center. and most famous sights all circled around smithsonian station.

why you need a guide and help from others? just park ur car in nearby VA or MD metro station.

except 1 situation, you don't ahve time to company your parents who speak little english. only in that case u need chinese tourist bus.