If you are looking for something in the general vicinity of 5 miles, and if you don’t mind doing a few of the miles on reasonably well maintained dirt paths, you might want to try the Annie Jones and Apex Lake greenways.
To start, park in one of the lots near the lake at Apex Park and start jogging around the lake in either direction until you get to the parking lot on Lake Pine Road. Jog east (left as you come out of the parking lot onto Lake Pine Road) along Lake Pine Road to Cary Parkway. Here you pick up Cary’s Annie Jones Greenway.
It begins at the intersection of Lake Pine and Cary Parkway on the corner diagonally across the intersection from the gas station/convenience store. Take the west branch of the Annie Jones Greenway to Annie Jones Park and keep going until you get to the end of the greenway then head back to Apex Lake, finishing the trip by covering the part of the Apex Lake greenway that you missed when you started.
The only tricky place is near the beginning of the Annie Jones Greenway where the trail branches. The west branch to Annie Jones Park is a sharp left turn shortly after you get onto the greenway. It is identifiable by a concrete slab that has been poured where the path branches off to the left.
Alternatively, you can stay on the main trail (i.e. don’t make the sharp left turn) and you will eventually get to the end of the east branch of the Annie Jones Greenway at Gatehouse Drive. Go left on Gatehouse Drive, left on Highland Trail, and then right onto McIntosh Court, where you will find the access point for the west branch of the Annie Jones trail. Take the west branch past Annie Jones Park, back to where it joins the main trail. Turn right onto the main trail and head back to where you started at Apex Park, again finishing the trip around the lake at Apex Park by covering the part of the trail you missed when you started.
There are several maps posted along the Annie Jones Greenway so you can’t get too lost.