John Hughes is an endurance cycling coach who provides a lot of free and/or very inexpensive training guidance that is overall good for randonneuring. My only quibble is a 3 week taper for like PBP, 10 days is enough for me but some like a lot more. NB: pay close attention to what John says is the objective in the 4 month base period and to the relatively low intensity that he prescribes.
Coach Hughes: Training for Cycling Brevets, pt.1
Greg Grandgeorge is an extremely successful endurance coach. I tried to get him to coach me but his dance card was filled. Nonetheless, he very generously answered my questions that I could not find answers to and seems like a phenomenal guy. He has canned training plans on TP that I cannot vouch for but all of his athletes stay with him for many years, so, he must be good. I raced with a lady who spoke the world of him..
[size=13px]https://www.tri2max.com/blog[/size]
https://www.trainingpeaks.com/coach/tri2max#trainingplans