Tampa girl here, well actually I live 20 mins. outside of Tampa, but never the less I know about I-4 all too well.
Yes, there actually is an alternate route. You would take the Suncoast expressway north to Brooksville.(It'll cost ya in tolls, oh & don't speed. The Florida Highway Patrol will be all over you!) Brooksville is SR50. So you'd take SR50 to 27. Then after you get on 27 you will come up to 192. Now 192 is right there...a few more blocks above it and you are on World Drive!
Do I recoment this way......NO! It is a lot of back roads and one lane roads.
This way takes you north of tampa, then due east, so you are coming up to WDW from the west side. Where I-4 will take you northeast and allow you to exit into WDW.
I hate driving I-4, but it is just something you deal with and hope everyone keeps moving. I will say that holiday weekends cause heavy traffic, mostly on Friday, Saturday, and Sunday. I am not sure of the times you are going, but if it is around July 4th, watch out! Daytona Interantional Speedway hosts the Pepsi 400 which is a night race. (Probably on the 2nd of July!)
Other then that you will be fine. The problem with I-4 is that people stop for NO REASON! Half of the time people break because they are approaching a hill. What, are theygoing to fall off the road! (It drives me nuts.)
I will say that they are still "working" on I-4 up around the Lakeland area up to 27. So the traffic may be a little iffy with the construction, although every time I drive up there as you are approaching 27 the traffic slows, you may even stop, but as you creep along past 27 it clears up. (This baffles me.) It is a hit or miss thing. I drive up to WDW all the time for the day and it is usually on a Saturday morning or Friday night, and I only really hit traffic around 27! There are other times when it is a breeze nd we sail right on up there. Just use your best judgement. DO NOT go through Tampa during rush hour. (During the week anytime from 8-9am i think or definately from 4pm-7pm at night. Leave around 10am. This way you will be up at WDW around 11:30 and you'll be golden!
I would take I-4.
