Does anyone know a faster way to obtain training droids.

This is common.  Training droids were a roadblock for me while leveling a long time ago.  Eventually things catch up though, and credits become more of the roadblock in terms of leveling the characters.  You just have to keep plugging away and to participate in the game modes to ensure you get a good income of them.  I think the training droid heist is currently active, which comes around on a weekly basis or so.  Having a Scoundrel team that is able to complete the highest tier in that as soon as you can will help too.