what is needed to be able to have access to a dropdown in JEvents with the locations I've set up in DT Register? Perhaps DT Register can auto populate an event location link within the JEvent details like it does with the register link?
There is no connection of location between DT Register and JEvents and there probably never will be. We're in the process of making JEvents optional... so going for LESS connection with JEvents, not adding more. With the upcoming 2.7, there will be no need for JEvents at all.