Not sure what you mean by " it's about equal to go through Orlando or drive down the coastal interstate" as depending on where in GA you are coming from you have a couple choices of routes, thought I have a feeling that may mean you are coming down I-75. The 2 main routes into FLA from GA are I-75 and I-95, with I-75 you do have a couple options according to MapQuest.
If you are coming south down I-95 and heading to KSC first, stay on I-95 the whole way to the KSC area. KSC is about an hour south of Daytona.
If you are coming down I-75, take that to the FLA Turnpike and in Orlando you get on Rte 528 (the Beachline expressway) to the KSC. (using Valdosta GA as a starting point it's 261 miles and should take 4 hours 3 min)
You can also head down I-75 and then take I-10 East, go around Jacksonville on I-295 to I-95. (that's 266 miles and 4 hrs 12 min from Valdosta)
A 3rd option from 75 is to get off I-75, take I-10 for about 5 miles and then take a combination of FLA state roads and US routes back to I-95 in the Ormand beach area just north of Daytona (only 259 miles from Valdosta, but a little longer at 4 hrs 21 min)
That said, an hour out from KSC is about Daytona coming from the North on I-95 and if you decide to go I-75 through Orlando, Orlando is about an hour out, so maybe you check into where you are staying in Orlando a day early if that's an option, that's figuring you are heading to Orlando for you trip . There are also plenty of places to stay near KSC. Stayed at one place right off I_95 for a Shuttle launch back in 08.
Hope that helps and I didn't confuse you.
