I would like to ask "Where do you want to spend the rest of your life after your retirement?"
Does "Where would you retire to?" have the same meaning?
For both sentences to have the same meaning, the underlying assumption is that once retired, the person would not move.
Where do you want to spend the rest of your life after your retirement?
is a clear way to ask your question
Where would you retire to?
asks where the person wants to be once they retire, however after some time (a few years) they might move else where.
So both questions are not exactly equivalent.