Many SplunkTrust members are User Group leaders - they are held in the highest esteem. Plus, it'll look great on your resume. And, as with most things Splunk, it will be fun!
Developing an active community takes time. Depending on adoption levels and the number of users in your region, it could take some time before you identify your champions and your regulars. If you keep bringing people together for active discussions on the topics they're interested in, the group will grow. If your group is getting 5-10 people together on a regular basis to share their Splunk world with each other, then it's a success.
If you don't have access to a conference room or similar space at your office, or at the offices of another group member—no worries! Splunk User Group meetings work well at a pub or restaurant that has a private room. This doesn't have to be formal. In fact, people tend to relax and talk more if it's not.