Passes to get into the centre or center! are free and can be booked online before your trip. Whilst you will have to queue to get through security once in you will not have to queue again for tickets. I queued for about 40 minutes. Rid yourself of any food or drink.
Jeremy handed me a headset which meant myself and the rest of the group could always hear him as we roamed the dome!
For an hour or so Jeremy was informative, amusing and ready to answer any question. He took us to the famous rotunda where we gazed in awe at the ceiling, statues and pictures. There is a statue representing all states and the ceiling is so cleverly crafted that it looks 3D
There are exhibitions in the Emacipation Hall about the history of the senate and congress, you can then walk through the tunnel to the Library.
Take some time to look at the government buildings around the Capitol, I loved the space and the fact there are no tall buildings/skyscrapers in this area. All this is near the
Smithsonian Museums and other places of interest in Washington DC. So you can combine a visit here with the Air and Space Museum for example.