We moved both of ours at 17 months. Our first got "bumped" from the crib because we were expecting the second. The transition was no big deal for either. For the first, we set the bed up next to the crib and left it there a few weeks. She played on it and got used to it being there. She was a hard sleeper, so one day I just moved her to the big bed after she fell asleep for her nap, so she woke up on the big bed. She didn't complain. Did it again the next day, then the next day put her to bed at night on the big bed. No complaints, so the next day my husband took down the crib while I took her out to play, and put a Fisher Price kitchen center in its place. She never asked about the crib. We actually used a full-sized bed, so she was literally too small to get down, and she wasn't tall enough to reach doorknobs until she was 2, so we didn't have a problem with her coming out of her room.
With our son, we had a toddler bed stage because his "big boy bed" is a captains bed, which is high off the ground. So, we took the crib down and put a big red fire truck bed in its place. I ran errands long enough for him to fall asleep in the car, then put him in the fire truck bed. He was delighted to wake up there! Just like his sister, he waited on the bed for me to come get him. It took a couple months before he realized this wasn't like the crib and that he could just get down. I was surprised he stayed put because he is a climber. In fact, we decided to go ahead and move him rather than wait any longer because I found him one afternoon trying to get a leg over the crib rail. I guess the fire truck bed was just too exciting to try to leave it!
Both times we moved all of the comfort objects to the bed with them. Blanket, stuffed animal....even laid the ocean wonders aquarium on the bed.