You're doing fine. It's obvious to me that you are in the process of figuring it out. Wandering farther afield stretches you because you have to ride back. If you ride loops, you keep having to decide whether or not to start another lap. If you wear a wristwatch try to convert your thinking from "miles" to "minutes". Do you really care how far you've gone or do you just want a comparative measure of how much you're doing?