ironchefmitty I would suggest to try Kevin Hill next. But search carefully for the longest episode, or invest in buying one from his website. This will be challenging, but it will give you glance into other painting approach in alla prima. Kevin I would say is transitional style between going into serious and more complex adventures with paint. I also would recommend after Kevin's tutorial to switch back to easier one with Bill as the way to depressurize.
Pretty much you got all the trio: Bill, Bob, Kevin who are good for starting and progressing to intermediate.
If you want to investigate more on trees and mountains. There is youtube channel Painting with Yovette where she goes into details how to get things done. Nice one to learn as well if you pursue landscape.
Another one is Mazart on youtube, you can search, there she does some animals too and you can get few ideas from her. I will wait to hear from community too about animals painting tutorials - I wanna try something new.
On a different note if you want to invest in your learning there is a subscription to www.nma.art where you can attend professional artist classes on paint/composition/drawing/etc.