Very easy. Just go up World Drive like you're going to MK. Get in the rightmost lane that isn't reserved for buses. When you get to the pay booth for MK, just tell them you're visiting WL and they'll wave you through, reminding you to stay to the right. You'll actually stay straight on World Drive in that right lane, while TTC parkers veer left. Keep going straight up World Drive until you reach the first major intersection beyond the TTC parking lot. 7 Seas (going to Poly and GF) is on the left and Timberline is on the right and goes straight to WL.
Tell the WL guard gate CMs you're visiting or have an ADR and they may give you a pass or just to tell you where to park, giving you the 3-hour limit.
Once you've visited WL, I personally would take the boat to FW. It's a separate boat that goes to FW from WL and it's a pretty quick trip. Plus you dock at the rear of FW, where most of the stuff you probably want to see is. If you drive, you have to park in front and then take an internal bus to get to the rear of FW. But if you still want to drive to FW from WL, get on Wilderness Road, which is between the guard shack and WL itself, and that road will take you to FW.