A few agencies (DEA & FBI, for example) do not tell you where you are going until you are most of the way through the academy. Most, however, will tell you where you are being hired to. So, you will likely know your first duty assignment before you decide on the job offer. How long you are there and whether the moves are optional will depend greatly on the specific agency.
With that said, I think it is humorous that you are trying to make long-term decisions (life-long career) based on a short term situation (finishing your contract). You may have some priority issues, if you ask me.
We bring evil things to evil people, kicking in a door near you!
."In theory, there is no difference between theory and practice. But,
in practice, there is."
- Jan L.A. van de Snepscheut
"The difference between 'involvement' and 'commitment' is like
an eggs-and-ham breakfast: the chicken was 'involved' - the pig
was'committed'."
-unknown
Working on a PhD in CQB one doorway at a time.
When the wolf attacks, he will find not all who run with the flock are sheep!