Just to be absolutely clear because I do not want to mess up my main character. Can I take my silver character (the Glacier) Click on the Convert button, keep my character as the Glacier, do nothing Gold related to said character. Then when my subscription is up convert it back to silver without purchasing a respec token or anything else? BTW do I just hit the convert button to make it silver again or what?

One last question if I then decide to go Gold again, can I change my Glacier character back to Gold status and then silver again without purchasing anything other than the subscription?

See my thread in this forum about silver/gold/silver/etc for details.

To answer your main question - if you stay AT you can switch between gold/silver infinitely without an issue of having to purchase a retrain.