I don't usually have a discrete bedroom block, I like to put craftsmen as close as possible to their workshops and supplies, so I lay out most of my fortress in little hexagonal work blocks with a couple beds each.
I start by dropping three staircases down into the area I'm going to be building in like so:
I'll be cutting out rough hexagonal areas between the stairs, but I don't start digging yet, just designate the area.
Each block will have up to 6 workshops (blue blocks), 2 beds(small B's), and storage areas for products, food, supplies, as close as I can get to providing everything the two workdwarves need.
For workshops that may be claimed by a dwarf in a strange mood, it's a good idea to leave some walls in place, so the only way to access the workshop is through a door (just in case you have to shut someone in). If you do dig out one of these walls by accident (or just want to use up some stone) it's easy enough to just reconstruct any walls you need. The specific square (or squares) dug out for doors depend on the workshop layout.
Just a side note, but one of the usual problems with putting beds near workshops is the noise, with the workshops spaced just wide enough, there are exactly two positions in the center where a dwarf won't have their sleep disturbed if someone starts working.