Now that I'm a little more recovered from the half century ride, I look back on what I could have done differently. The ride itself was fine and the nutrition for it also seemed fine. What I didn't think about doing was being prepared afterwards for the exhaustion.
The post-ride temptation to fuel up on carbs was heavy. My body was craving them like mad. The temptation wouldn't have been as strong had I pre-prepared some foods to eat that were waiting for me at home which required no extra energy. Have the big salad already made and chilling. Have the meat already cooked (if eating meat). I should have been ready, and I was not. I also should have had at least a gallon of water chilling, because I had an insatiable thirst for many hours afterwards, and not only was it insatiable, I only wanted something COLD. Again, I was not prepared for that, but I'm in a learning process, and the learning curve is high for me. Next time I'll know these things... because there will be a next time. Not sure when, but there will be one. This weekend?