If you are able to get a good price, I would also suggest the Kameha Grand. I have stayed there once with a dinner package and enjoyed it very much.
Their restaurant "Yu Sushi Club" is currently awarded with 15 Points in Gault & Millau Germany 2014.
The hotel is located about 500m away from a tram station (Ramersdorf) and a train station (Bonn-Oberkassel) with trains to Cologne and Koblenz.

Another good options with convenient location I know are:
- the "Hilton Bonn" next to Bertha-von-Suttner-Platz, a kind of transport hub for trams and buses and adjacent to the pedestrian zone
- the "Villa Godesberg" about 300m away from Bad Godesberg station (train and tram)

For dinner, there a some options in and around every one of those hotels. But travelling by tram will increase your options and wonīt take much time since Bonn isnīt called "Bundesdorf" ("Federal village") for no reason ... ;-)

/Edit: I would not suggest to get a hotel next to the central train station / Hauptbahnhof because this is an area with some drug abuse problems and many cheap shops which attract not the nicest kind of people ...
Better get a cab or a short tram ride and have a nice view.