Congrats on your mileage. BTW, age has little to do with it. Time and opportunity to ride are the key factors! For a point of reference, I'm 64 (not in zona's stratosphere yet
), and I've ridden over 5000 miles (8000km) this year. Most of that was commuting 30-32 mile round trip, most of the rest was on a tandem, and some was riding solo whenever my sweetie would agree.
I'd say go toe clips because you can use any shoes. You needn't tighten the straps down especially tight, but unless you are wearing cleats or running shoes with deep slots you won't have any trouble pulling your feet out in a panic scenario. Many people argue that they don't offer the power potential of clipless, which is perhaps true. But depending on how you use your gears your limit for speed or climbing over moderate distances will be your aerobic capacity, and over longer distances will be how you eat. Power
per se may let you accelerate a little faster but if you aren't racing anyone that doesn't matter.
I'd also say go to a drop (road) bar. Not so much because it lowers your wind resistance (though it does a little) but because it offers more and better hand positions and it changes your weight distribution on the bike. There are reasons the drop bar evolved as it did. For most people having the palms face inward is more natural than having them face downward. Leaning forward a little gives you more power. And moving the weight of your arms ahead of the steering axis gives you better stability.
All my bikes are vintage steel road bikes. I have no discomfort riding them in urban settings. I spend most of my time riding the hoods, and have no trouble braking. They even have friction downtube shifters. I know I wouldn't like clipless pedals or index shifting or carbon fiber frames or brifters. I've never eaten some foods so I just know they won't taste good. Bike components are the same way.
Take all this with a grain of salt, of course.