Okie ... As mentioned in one of the answers u really dnt need a guided tour in BAsel..Its small for that ..yet its a beautiful city ...
For other sight seeing information u can visit this link
http://www.baseltourismus.ch/
but I doubt if u wud be so intersted in the museums!!!
The first thing i suggest you to do is to visit the travel office just on the stop called Barfusserplatz and find out if there is any day card / special travel pass available to travel in the trams here . If u take tickets to everyplace then it wud be quite costly .... A day card can cut down on that cost if u ll using the bus/trams the whole day ....
The spot i think u wud enjoy are The banks of the rhine mainly .... its a relaxing place and beautiful ....there( see a board rhine romantik) u cud take a cruise ... its arnd 60 chf per person and they will take u on the rhine cruise for 3 hrs ...it wud be a good thing if u r willing to spend that much .....
Second wud be the roman town of Augusta raurica ...
For all details u can visit the site i mentioned...
hope this was useful and have a great trip ...
PS: there is an exhibition square called messeplatz here ... u can also check if any good events are held there at the time u will be here ...