Thanks for writing in. I’glad your head is full after reading the book and I hope that you will want to refer back the book many times. That is why we call it a manual.
As to your questions:
1) the recovery time after any major event is entirely individual because it is related to how deep you had to dig to complete said event. If you’ve run a number of marathons and have an extensive training history then a 3-5 weeks might be sufficient rest before you engage in training again. If you do not have an extensive training background in endurance running then 6-8 weeks could easily be required.
2)For long term progress and development the base if critical. But for short term performance gains you do need to have more event specific training. To shorten the preparation period will me some sort of compromise. This will depend largely on the state of your aerobic base. More base will allow more specific work. Less base means you need more base development.
I hope this helps.