My advice is to do what you feel like, you're a runner now!
For me I signed up for a 5k and have done a 5k every weekend since I've completed the program, except for this past weekend when I got brave and ran a 10k. The races helped me push myself a little (it's easier to run faster when everyone around you is runnin fast). I also started the bridge to 10k app which was useful, but not nearly as exciting as this app (it was more dry just run or walk, no one gave me permission to slow my pace if it was difficult). A few weeks after finishing, I've come to realize that I can basically run for any amount of time or distance if I pace myself accordingly, hence the reason I signed up for the 10 k (ok I really signed up because a friend and I wanted to run the farthest distance ever, and the race started at 9:00, and by 8:30 no one had signed up for the 10k, because most were doing the 5k and we thought we might win if no one else signed up hah)
Now that you have finished consider the aspects of running: distance, speed, and hills are things that most runners work on. It doesn't make since to work on all three at the same time, but on Monday you might work on speed and do fartleks, Wednesday you might work on hills, and Friday you might take a slow easy pace and do 3 miles without worrying about time.