[Cookiemonster]

You don't want to know how many fricken doors I've done in this manner.

I prefer not to work with pine as it sucks to stain, IMHO. I've had customers requesting "oak" with pine. I've seen guys brush on oak wood grain to pine but the price triples for labor.

Enough of that.

It is always easier to stain the jambs prior to install. Take the doors off, remove the hinges and stain both the jambs and door.

Re-attach the doors and install the unit.

Remove the doors and seal up jamb and doors with at least 2 coats of what ever you're planning on using. Typically the jambs you can get some good quality foam brushes and brush a nice Poly on. I prefer to spray the doors as it is a nicer finish.

Try and hide your screws under the weather stripping or flashing. Thus you haven't a need for filler. If you find yourself using a 15 or 16 gauge nail gun go easy and find the stain filler to match, but make dang sure it matches dried before you go using it else it look like crap.

Good luck and better you than me.....