Regarding your question about balancing internal and external activities so that neither suffers, the solution is to place your emphasis on your internal activities. This does not necessarily mean that you give your internal activities more time than your external activities. It simply means that you establish it as your topmost priority and don't deviate from your sadhana. By cultivating an attraction for your internal activities, you will be able to execute your external activities with less attachment. They must be performed, but simply as a matter of duty. You will not be dependant upon satisfaction from external activities because the satisfaction coming from your internal activities will be far superior. But if there is excessive attachment to external activities, then it will adversely affect everything else that you do, and both your internal and external activites will suffer.
Collected Letters Written to Friends and Disciples Vol 4, Pg 15, 2nd Paragraph