If you are looking to come to Washington DC in the near future, there are a few ways you can visit the city. You may choose to see the city on your own. This can be fun and it can be frustrating at the same time, especially if you want to see certain attractions or visit sites that require a ticket. The reason for this is that for some attractions, you have to know when tickets are available and when the "heavy traffic" time is for certain places (National Archives, for example).
The next way you can see the city is to take one of those one-size-fits-all tours. When you take these, you are at the mercy of the tour company. Plus, if you want to see something up close and personal, you are going to have to go back at a different time to do that, as many of these bus tours do not stop.
There are hop-on-hop-off options and these can be good. There are schedules available to follow, but once again, you are at the mercy of the company and their buses will not wait for you. One personal acquaintance of mine had foot surgery. She could not run to the last bus of the day even though they were only 20 yards away and waving frantically at the bus and he saw them, he left!
The best way to see DC is to schedule your very own private tour of the city. You work with the guide (like KB Tours) and settle on the itinerary to follow. It is all about you.