I’ve used 1x4s as side casings and 1x6s for the header, so I’m trying to keep all the doorways or doorless entryways the same as the window casings; but I have a spot where the entryway to the bedroom hallway will not fit the full sized casings and another spot where the entryways and a bedroom door share the corner and don’t have enough room between them for the full casings.

What do you do in these type of situations?