Robinette,
I've driven several times from Central PA and from Philadelphia, depending on where I was living at the time. Once you get past Central Jersey, our routes should be similar.
Bottom line, if you're looking for a quick trip (and I know no one who wants to prolong that particular trip), get to I 95 ASAP and take it straight down to Daytona, where you catch RT. 4. It's around 18 hours, give or take for meals and pit stops.
We've always, for some reason, stopped in a place called Walterboro, SC. It's about an hour short of Savannah. That way, you're getting two thirds your trip in on day one, so the jog to Orlando is short (if you consider six hours short). We find that after about twelve hours driving towards Orlando, we run out of steam. Walterboro is a small town off I95 that seems to make its money by catering to folks running out of steam on the way to Orlando.
What you'll find is a clean, safe town. I noticed right off it was tough to find a drink, which usually bodes well for the safety factor. There is inexpensive gas, lot's of restaurants and convenience stores, and everything from major hotels to little places where you can get a room for under forty bucks a night. And there's a Krispy Creme, important fuel for the final trek.
Anyway, that's what we do. Warning: if it's your first drive down this stretch, AVOID SOUTH OF THE BORDER. Located just over the line into South Carolina, they advertise the place starting just south of DC. You'll think you're approaching Mecca. As it appears on the horizen, you'll be drawn to it. But what is it: It's like someone took a bad boardwalk from the Northern Jersey shore, gave it a Mexican theme, and moved it to South Carolina. Bad food, bad shopping, a really bad casino. And boom, you're out an hour of your life. Don't do it. Eat at a Stuckey's instead.
Pat