Sure you can, especially if your permissive is tied directly to your terminal leave. I know guys who have done it - nobody will care what you're doing on your own time. If you really care about the reg (36-3003), it says you can use PTDY "for a pre-separation or retirement relocation activity such as job or residence search"
The reg is vague, but if you really felt you need to follow your inferred intent of the verbiage you could consider job training as a "retirement relocation activity".