I decided to attack transferring the PCB again. Following the unsuccessful attempts the last time around, I made a few changes in my approach.
First of all, I was more diligent about getting coverage and heat with the iron. The second, I read a few additional methods that mentioned preheating the copper board first prior to applying the toner image. And finally, I came across another site that mentioned using overhead transparency film in place of the photo paper so I added that to the mix as well.
Here's the first attempt (#4 overall) with the overhead transparency. It wasn't perfect but is the best result so far. I think I might be able to repair some of the incomplete tracks with a Sharpie before attempting to etch. Another positive feature of using the transparency was, if you are careful, you can hold one end of the film and gently lift a corner to see if it is transferring adequately.
Still, I wanted to make it work with the photo paper, so on to attempt #5. This was the worst yet. I preheated the board as with the transparency, was very meticulous about coverage with the iron, and it hardly transferred at all. I give up with the photo paper.
Since the copper board is double sided and my design is only a single layer, I intend to etch circuit on both sides. That way, I can choose the best one and just sand off the other side. As I did #5 on the back of the same board of #4, I just cleaned off #5 using some Acetone and re-scuffed it with the Scotch-Brite to get ready for...
Attempt #6, back to the overhead transparency. This is the best yet. Again, it's still not 100% perfect but I think it's good enough to use to test the etching process.