The Honour Plate is in the courtyard of Hotel Basel, which is located just off a street in Marktplatz (the main market square in Basel).
If you are coming by train from the Basel SBB, take No. 8 (direction Kleinhuningen) or 11 tram (direction St. Louis Grenze) and get down at Marktplatz. There you can ask anyone where is Hotel Basel. Its just 150 odd metres from the tram stop.
If you are coming from the airport, take No. 50 bus to the Basel SBB station and then follow directions as above.
Enjoy, I was there when the honour plate was "created" and it was a great occasion.
Oh no zürihegel, c'mon now, even if you don't like what you call "personality cult" you must admit Roger has done a mighty good job and deserve a bit of attention no?