As the Tampeno here, I must say that it sounds like too much of a rush/hassle to try to get back and forth between Tampa and the beach. And Busch Gardens is like Disney. No way would I do that.
Now, since you are coming down from Homosassa Springs (which is north of Tampa St. Pete on US 19), why not check out Tarpon Springs? The Suncoast Parkway is a great new (albeit expensive) conduit connecting Tampa to Homosassa, and it runs by Tarpon Springs, sort of. You'd get off by the ritzy country club community of Cheval and drive west to the water for about 20 mins to hit Tarpon Springs, drive back to the parkway then head to South Tampa and Berns.
Or, you could take a "leisurely" drive down 19 to Tarpon, which is one of the great undocumented chow streets in the US, chock full of strip malls with ethnic and US regional stores and restaurants. But there is no LTH in Tampa and no Jonathan Gold. On the other hand, US 19 is brutal in its traffic, speed traps, and urban blight (those same strip malls).
Sarasota makes no sense, since it is an hour in the wrong direction (south) from Tampa. I'd say the same for St. Pete.
South Tampa/Palma Ceia near Berns is worth checking out if it's not too hot. It's like a tiny version of West Melrose in LA. In the same area, Bayshore Blvd. is one of the great streets of America. A miles-long promenade along the Bay past beautiful houses with a view of the city.
Ybor also is well worth another look if it's been 20 years. Much more touristy and plasticized, but the heart is still there. A cup of coffee or a brandy at the Columbia might be nice. Sunday afternoon, you'll have the place to yourself. If you smoke cigars, it remains the best place in the US to buy them -- particularly the Fuente and JC Newman brands (probably the best non-Cuban lines). Both families and their businesses remain in Tampa. There are also some solid local rollers.
If it were me, I'd jump on the expressway, check out Tarpon Springs, jump back on, check out Ybor, take a drive downtown and along Bayshore, then go to Bern's. TS and Ybor are unique in Florida -- two very old, intensely ethnic neighborhoods (Greek (TS) and Spanish/Cuban/Sicilian (Ybor)). Do seriously check out Steve's and Dmnlky's posts. They did plenty of research and leg work for you already.
Or play a round of golf. TPC is on the way.
PS, I'm a long time fan of Malio's (old dark and clubby version) and have some connections there. I tried the new fancy downtown location some months back and agree that it is very, very good. And the view of the minarets at UT -- widely regarded to be the best example of Moorish architecture in North America (at least the fantasy Moorish Revival of the late Victorian era) -- is hard to beat. I still miss the old place -- where Burt Reynolds used to cruise in the '80's and George Steinbrenner inked many of the greatest trades in baseball, among other things.
Then there's the famously seedy side of Tampa. I won't get into it, unless asked.
PPS, both Ted Peters and Keegan's, noted in my response in the SteveZ/Dmnlky, have been "discovered" by that "Dumps, Drive-ins, Diners and Dives" guy on Food. Keegan's chef is a classically trained Spaniard who takes fresh local seafood and does great things on the cheap. You must go to an oceanside place like Keegan's or Rusty Bellies for that kind of food and a cold beer.