We say either "în" or "la." In this case, I'd say you can use
Am fost în Tampa. (literally "I was in Tampa" -- we use it to mean "I went to Tampa")
Am mers la Tampa. (I went to Tampa)
I'd personally pick the first.
We discussed the rule, but unfortunately the thread is in Romanian: La sau în Bucureşti. In a nutshell: there may be a rule but in some cases they can both be used.
(natives probably choose based on what sounds better )