I had four goals at the beginning, so I'd like to share what I've learned from each of them:
1. Asses how reasonable my goal of biking 1,000 miles in 3 weeks is for my senior project
I'd say it's pretty reasonable. The takeaway is that 42 miles/day is possible, but the longer one individual ride is, the harder this goal becomes. For example, two 21-mile rides a day is very doable, but one 35-mile and one 10-mile ride is very difficult, and a 42-mile ride a day for three weeks is nearly impossible.
2. Learn how to create a proper cycling training plan
Yep, definitely something I learned. Although it's not really something incredibly novel. Like training for anything, as long as you follow the principle of "do something, and when it gets easy, make it harder," you should be fine. Yes, there are strategies of HIIT and endurance rides and things like that, but there are too many buzzwords that all just tell you to basically train hard.
3. Become more physically fit
At the start of the week, I climbed a certain hill at 4:29. By the end, I got it down to 4:05. Lots of this is rust being shaken off, but still a significant improvement. I also lost about 5 pounds, mostly from water, but still a good amount. I feel much better as well after not having done cardio for a while.
4. Become a better cyclist
Definitely. I've always felt comfortable on the saddle, but going to school today I actually stuck my hand out to signal in my car. If that doesn't signify a good cyclist, I don't know what does.