David,
Thank you for your response. The JIRA access information is going to come to us as a file -- it is not something that a user is going to type in. At most, the location of the file is something the user can input into a settings form. Creating a form to type in just that info seems to be a lot, especially given my limited abilities and bandwidth. So finding the site directory from inside the extension remains the most feasible option we have.
The Extensions feature that you have, that enables a user to customize RB for their team's needs is very impressive and powerful. Thank you!
Kartik