Here's how I'd get there...
Depending on where on 27 you're starting from go either north or south to the intersection with Route 192.
Go about 4 miles on Route 192 (you'll pass the main entrance to Orange Lake Resort on the left) and then turn left onto Route 429 (the Western Expressway).
Take the first exit to the Western Way. Turn right at the end of the ramp.
Continue on the Western Way to its end at Buena Vista Drive. Turn left onto Buena Vista Drive.
Stay on Buena Vista Drive for 2 1/2 to 3 miles and turn left onto Bonnet Creek Parkway (may be called something else now, they've changed the names of some of that area's road, but you'll see the sign for the Old Key West DVC at that intersection).
Riverside is straight ahead, you'll pass Old Key West and Port Orleans French Quarter before you get to Riverside.
Dick Taylor