You are very close with what you have now. There are two problems that I can see based on your description. The first thing is that the select list for destination should have the name of the destination as the label, and the id as the value.
When it is like this you will create the recordset based on the posted value like you have done. The difference is that you will need to filter the rs using the DW filter options. When viewing the recordset remove the where clause and go into simple view. In here just select the table and the rows that you want to return, then below this part in the filter section choose to filter the locationID on the form value that holds the locationID. This should be your location select list, just enter the name of it.
When you get it setup like this it should dynamically load the info for the selected destination after the user submits the form.