I will be changing the order of the layers as folks look at them and decide they want different groupings.
I have run into interesting problems. My first problem was that I didn't have the permissions to do analysis, and it took a while to be made an administrator to get the proper permissions to do analysis. I then was able to add a watershed tool, and a buffer tool. These are mostly for fun (me playing with things). I tried to add download data, but my map service is not a feature service. I found out through a lot of searching around, that I have to have my data in an enterprise geodatabase to make it a feature service (someone can tell me if I'm wrong about that).
This application will continue to evolve, hopefully more after I attend a training in Portland. Watching the on-line seminar really helped me figure out where the widgets were and how to add them.