You are right there is never a perfect day where all the stars align and you suddenly say "hey, let's go to the gym!"
You have to set a goal, like Nik says and then make
the time - you rarely find
the time... if you know what I mean. Even in the 'burbs you should be able to find an interesting stretch of road or trail to run. Just keep looking. Maybe that's Goal #1: Find a good street/trail/park. Then Goal #2: Get up one morning (I know you aren't a morning person, but personally if I don't get it done in the morning it just won't get done) and go.
It is usually just getting over that first hump (energy of activation in physics & chemistry) and then the rest of the pieces will fall in.
And BTW the mean Super Moderator says "SNAP OUT OF IT!"