The closest one can get without getting clearance to enter KSC/CCAFS would be on the northern shore of Cocoa Beach/Cape Canaveral (town). From this vantage you're about 14 miles from the pad and it's accessible from Tampa by taking I-4 to FL-528 (Bee Line) in Orlando and continuing to the beach.
If you get as close as you can, you need to keep in mind that countless thousands will also be trying to get as close as they can...so it's close to chaos trying to get out. Don't plan on going to work the next day as it'll take you a few hours just trying to get out of whatever parkling lot you're in.
I'd avoid all that and make a U turn back onto 528 East and find a spot on the bridge from the mainland to Merritt Island.