Danube bend

(Dunakanyar), a string of small riverside towns just north of Budapest, is a popular excursion spot for both international travelers and Hungarians. The name "Danube Bend" is actually a misnomer, since the river doesn't actually change direction at this point. The Danube, which enters Hungary from the northwest, flows in a southeasterly direction for a while, forming the border with Hungary's northern neighbor, Slovakia. Just after Esztergom, about 40km (25 miles) north of Budapest, the river swings abruptly south. This is the start of the Danube Bend region. The river then swings sharply north again just before Visegrád, and then heads south again before reaching Vác. From Vác, it flows more or less directly south, through Budapest and down toward the country's Serbian and Croatian borders. The delightful towns along the snaking Bend -- in particular, Szentendre, Visegrád, and Esztergom -- can easily be seen on day trips from Budapest since they're all within a couple of hours of the city. The great natural beauty of the area, where forested hills loom over the river, makes it a welcome haven for those weary of the city. Travelers with more time in Budapest can easily make a long weekend out of a visit to the Bend

Editor's Tips
Ok visit, but when? - it is better to go from spring to late autumn. Most tourists there in summer, autumn season.
Go but by what? - in my opinion, to go and come back by boat is really boring. Go by boat its fun and interesting, but only one way. Try the train on your way back, the trains are ok on the danube bend line, going quite frequently and CHEAP
Any event? - The Palace Games in Visegrad is a must if you are around that time. More..
Best route - the best route is to go till Esztergom by boat. There are boats which stop than at Visegrad and Szentendre as well.
Go alone or by an organized tour? - it really depends on you. If you are a discoverer type, does not mind to wait for buses, trains, boats, you can easily go by yourself. Organized tours maybe give you more prospectives if the tour guide is ok.