We drove our 38' Dutch Star pulling the Jeep from Panama City Beach to Crystal River in January on 98, 19, 20 etc. Very easy drive through the area.
Ended up at the Tampa show, then too I-75 /I-10 west. Long boring drive. The interstate route also leaves you about 70 miles north of the coast. Depending on when you drive 98 can be pretty congested through Panama City / Panama City Beach. (Especially March / April - Spring Break time)
I'd take the backroads again.