Hey FatDad,
Congrats on your PR and breaking 2 hours!
Here are my answers to your questions:
1. Time between plans,,, it depends. If you have been training pretty continuously for 6months then a full recovery period might be needed. This can vary but anywhere from 2-4 weeks works for many athletes. If you are still in your season training block and moving from one race to the next, again it will depend but 3-10 days is a recovery range depending on your fitness and how the rest went, with a return to some base training for an additional week.
2. Yes you can get faster repeating the same plan – you will get more efficient, stronger, and improve your LT pace/power etc which will allow you to execute your sessions at new efforts improving fitness. More volume is not always the answer for all athletes, particularly those over 40. Ensuring your executing the plan you are following and incorporating strength and mobility plus sleeping and eating well will support improvements more than just adding more volume
3. The level 2 plan has a recovery run on the standard rest day, but also has more volume and therefore more intensity through the whole plan. A simple way to slightly up the volume of a Level 1 plan is to include this recovery run if you feel you don’t need a full day off.
Hope that’s helpful.
Happy Training
Coach Leyla