Landscape commission on my easel

I've been busily working on a commission just lately... also trying to do a few other things at the same time, but this shows the progress I'm making on the commission.  It gives a good progression from rough sketch to beginning to apply paint - and now beginning to get some details put in. 
It measures 20 x 24" and I started by toning the canvas a tint of violet.  The rough sketch is made from a group of reference pictures I was given.  The rough sketch is at the top.  Then, I did an oil sketch on the canvas and began blocking in some shadow areas.  Finally I painted the sky, trying to pay attention to the altering colors of blue withing a clear sky.  Then, I began putting some details in with the trunks of the tree in the foreground.  It is weathered and gnarled, but yet quite graceful.  And in the last picture, you can see some of the back ground mountains and cliffs.  Its obvious I have a lot more to do, but it seems to be taking shape.  I will post the progress I make in the coming weeks.