Welcome. Henry E. Kinney tunnel?
How hardcore do you want to go? No AC? It is too hot already and it only April.
Instantaneous fuel display imo a must have. As for South Fl being flat you would think so but if you drive I95 every one of those overpasses uses more fuel on the up side. If you use the turnpike, SunPass. Take a look at the 100+ Hypermiling Tips if you haven't. Tip 41, 42 and 43 deal with cruse control or not.