M.F.
We moved our first when she was 17 months for the same reason. She was 22 months when our second was born. We used our full-sized guest bed. We set it up in her room next to the crib and continued to put her to bed in her crib for a few days. At the weekend, we ran errands until she fell asleep in the car, then put her in the big bed already asleep. The next day I took her out of the house while my husband disassembled the crib and put up a play kitchen in its place. She ran into her room, excited about the kitchen, and didn't say a word about the crib being missing. We put her to bed in the big bed that night, and she's been there ever since. We never had a problem with her staying up late, coming out of the room, etc. Seems like from my friend's experiences, the younger they are when you move them, the smoother the transition (in general, that is).
It was so easy at 17 months with her that we did the same thing with our second child (even though there was no sibling coming along to kick him out of his crib). It was just as easy with him!