I hate to say this, but it is a little luck and trial and error. I have 4 kids, the first three, no problem. My youngest has slept with us since birth, and we just now got her into her own bed. We tried a toddler bed with Nemo (she loves the movie) bedding, and she hated the bed; would not stay there. We just recently got bunk bed for her and her sister (they share a room), she has the bottom bunk and we got real cute pink/purple butterfly sheets/comforter set and now when she wakes up int the middle of the night - rarely, but it still happens - she wants to stay in her own bed!!! I was surprised when she did that for the first time!! LOL!! Also, we had just moved into our new home 4 months ago, and she has had her new bed for about 1 1/2 months now, and she still loves her new bed!!!
My advice is to wait until you get to your new home, since you will then know how big a space you have to work with, and even if you get a regular twin bed, they have bed guards to keep her from falling out of bed and they are fairly inexpensive. That is what I have for my daughter and it works great!
Also, let her be part of the process, she can help pick out her bedding and then she will feel ownership and hopefully should ease the transition to her new bed.