We did this and it was wonderful.
Gave us plenty of room and the safe option of baby having her own area - excellent for when you are exhausted and not able to be as aware as one should be while co-sleeping. Best of both worlds.
(Dh has his own room now, but that is because he is a night owl and wants to read until 3:00 AM.)
We used those same instructions linked above.
1) Take off the moveable rail of the crib.
2) Allign the open side of the crib with the Momma side of the bed.
3) Shove a very tightly rolled blanket on the RAIL side of the crib mattress, between the mattress and the railing, pushing the crib mattress up against the adult mattress, tight, flush and firm.
4) Lash the legs of the crib to the frame of the adult mattress using zip ties and c-clamps.
5) Place a blanket across the joint between the mattresses.
6) Fill in any corner gaps with very tightly rolled towels.
7) Make sure that the headboard on the adult bed is safe, no gaps.
8) Make sure the adult mattress does not drift away from the crib mattress.
- We lashed them together using bungee cords in the mattress handles, hooked onto the FRAME of the crib, under the crib mattress. I think that is included in the instructions.
9) Inspect the set up every day to make sure there are no gaps, dangers, etc.
I used a layer of firm foam underneath the blanket to reduce the friction from the cable-edge of the crib mattress... I always seemed to wind up sleeping on it!
When we have another baby, I am going to sew a fabric-covered foam T-shape insert that can slip inbetween the mattresses and cover the edging at the top.