Thank you to everyone for suggestions and feedback. This morning I rode with both my iPhone running RWGPS and using my Cateye Velo cycle computer. RWGPS is an interesting app, and maybe I'll continue to investigate it. I had my phone in a jersey pocket, so I couldn't get real-time updates, but my little wired Cateye always has that info available. I have prescription single-vision sunglasses, so reading text on my iPhone with dark, polarized sunglasses is nearly impossible anyway. All in all, while using RWGPS may give me a wealth of information about my ride, the fact is, I'm an older rider who rides to enjoy the outdoors and stay on the green side of the grass. Being able to track time and distance on my Cateye is really all I need. I don't measure a ride by watts or anything like that.
Today was a beautiful, if breezy, sunny and warm day in Central Florida, and my ride along the Indian River Lagoon was really nice. Most days, that's all I need. So I'll stick with my dinosaur Cateye solution for now.