I've been fishing the Withlacoochee River / Lake Rousseau area for 10 years or so. Its north of Tampa with nothing else in the area (except in-laws!) but the place has some big bass. I usually don't shiner fish up here but its your best bet for a big largemouth in FL. Personal best is 10 lbs even, with the usual big fish around 8 lbs. 15 to 18 bass per day is average, with half at 5 lbs or bigger. Fished with my brother years back and his top 3 were 12, 10.5 and 8.5 lbs. His picture is still up at the bait shop years later! The trip is usually taken in mid April although I did take a trip in early January once. My guide says that March is a great time to go.
I hear that Rodman is excellent. From what I've read, most of the Cross-Florida canal lakes have a lot in common. Lake Rousseau and Rodman are loaded with big tree stumps and huge bass. I think the biggest problem is that the state and county constantly mess with drawdowns and herbicides to keep the weeds under control. Homeowners vs. the bass fisherman - the age old battle! Keep an eye out for gators too. You don't see too many gators up here, but I've seen them up to 10 feet long on some trips in FL.