There are several really good tangled cakes on here, including mine so a search they should come up.
If it's the structure your worried about, I used a round wooden base, attached a PVC pipe and then put a smaller round wooden disk on top. I used RKT for the tower structure and did cake for the top of the tower house part.
There are a lot of cakes lately that have been done you could search for reference on how to decorate it.
Tengo publicado aqui un pastel de Rapunzel, puedes mandarme un mensaje si necesitas información de cómo hacerlo.