Unlike chandeliers, where you have a specific placement height, curtains and curtain rods don't have that specificity. It depends on the room, on the curtains, on the location of the window on the wall, and probably some other factors I can't think of at the moment.

If you post a photo of the window and maybe of the rod and the fabric, you will get opinions on what to do. Currently the fad is to "hang-em high," that is, to mount the bracket near the ceiling. But that's not the best solution for every window.

If you never intend to close the curtains, could you use the short rods...I believe JCPenney has them or Lowes. You would put them on each side of your window.

1) Is 4" from the window the right place to end the rod (before the finials)?
Depends on way too many factors.

2) Where, relative to the window frame (no molding) should the brackets be placed?
That would be your personal preference. I do not like them too high myself.

3) Where am I supposed to find time to make the panels for the guest room?
No one finds time... they MAKE time. We all make the time to do what is important to us.