Paneling and Trim - Uneven door and window jambs

We sheetrocked our 100+ year old house, and left the solid six panel doors in place. However, the jambs are terribly uneven, so that the top of a door jamb may extend an eighth of an inch or more, but the bottom may be as much or more, shallower than the rock.

I'm wondering how to deal with this. Plane down the high areas? That's do-able. But how to "shim" out the recessed jamb areas?

Shimming uneven studs is best done before the drywall is hung. But at this point, a belt sander would probably be the best tool to flatten out the jambs... just be careful not to scuff the drywall beyond the trim. If it's recessed, either your trim will have to tip in toward the jamb, or the drywall will need to be scored alongside the trim and beat down.

The walls have been shimmed, and are relatively plumb. It's the doors and jambs that are out of whack. I plan on using a power planer on the high spots on the jambs, however, not sure what to do about the recessed areas of the jambs. It's the windows and doors.

Stuff didn't have to be built straight back in those days, with plaster and lathe, I guess.

I use a discarded wood chisel to shave down the drywall when it extends past the jamb. Mark a pencil line so you do not get "out of bounds" past where the trim will cover, usually in 1/4 in. or so. Good luck with your project.

I like the idea of scoring the sheetrock and embedding the trim in it, however, how do you control the depth of the "bed" of sheetrock for the trim to lie in? Doesn't the rock just kinda crumble up? Won't the paper face fray?

Mark the drywall with a line slightly to the inside of where the casing will land on the drywall. The installed casing should cover this line. The drywall to the inside of the line(between the line and the jamb) can be chisled down since it will be covered by the casing. Score the drywall paper with a knife along the line before chiseling.

I like the idea of scoring the sheetrock and embedding the trim in it, however, how do you control the depth of the "bed" of sheetrock for the trim to lie in? Doesn't the rock just kinda crumble up? Won't the paper face fray?

Just to clarify what I think Wirepuller is saying... you don't "embed" the trim in the sheetrock, you shave the drywall down at an angle in the area where the trim will cover it. So the outside edge of the trim is not "embedded" in the drywall, but shaving the drywall allows the trim to "tip" at a greater angle, so that it can both contact the wall and the jamb tightly.