If the OP is interested in improving his MPH averages, I think that's a good sign of life. If you want to ride faster, two things work in tandem for that: riding more, and riding faster.
Riding more: Take a longer commute route home, even much longer if you can wear real cycling clothing, like up to 30 miles sometimes. But one way or another, gradually increase your weekly total mileage. Keep track. Set goals, Try to increase weekly mileage by 10%/week to start with. You'll hit the wall with that pretty quickly, but then you'll at least know what your current limits are, and they'll very gradually increase. When I was just starting out at 50, on weekend rides I'd ride away from home until I was tired, then ride back. I only had to make the call of shame a couple of times.
Riding faster: once or twice a week, ride a shorter distance than usual, but ride it as hard as you can, hard enough that you think you're going to have a lung up. Hills are especially good for that. See hill, ride up it.
It looks like you live in a nice rural area. If you live on or very near a paved road, no need for bike trails. Just go out the door and ride away. You don't need bike trails to be safe. Statistically, you're actually safer on the road. I mostly ride on two lane roads with no shoulder. Not a problem as long as you stay away from high-traffic roads at commute times. The nice thing about riding with cars is that car drivers know what they're doing and drive predictably. So you ride just as predictably. Stay to the right and hold your line.
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