How do I generate campaign level reports for the past 30 days?

You can't really do this with the existing reports.
 

What you might try is running either a smart list or a Lead Performance report with Activity Date or Created At and Group by that. You'll have 4 reports.

What precisely are you trying to report on?

I want to look at overall activity for a given period of time and then break that down to the campaign level so that I can see the key stats per campaign that roll up into an overall number for the month or 30 days, etc.

Which activities and which type of campaigns?

Other places that might help:

• Program Performance which can break down Net New, Success, and ROI basics for a time frame.
• Campaign Performance - focuses on # qualified, so it could be helpful.
• Lead Performance - you can group by a number of fields and constrain by smart lists, campaigns, programs, as well as Created Date (of the lead). The Smart List would be where you constrain by date of activity.
• RCE - if you have this, you can do more on grouping and pivot tables.