Essentially, we have 2 types of activities for outreach: Those we schedule/plan/run and events where we are invited to participate as part of a larger demonstration.
How does your team decide what events to do, in either category? Do you attend every event that calls for a FIRST team? Is your robot always part of your outreach? Do you do a cost-benefit analysis on committing resources? Do you only do local activities, or do you participate around your area/state?
We decided what event to participate in by 2 simple questions, " do the people at this event benefit from having us there?" and “does this venture get FIRST and our team out there?” if the answer is yes, we try our best to attend the event. If an event calls specifically for a FIRST team… we do try our best to go since usually there are more FIRST teams and getting to know other teams and check out their bots is always really helpful. Robots are not always part of events but I do try to bring it to every event I can, its a good wow factor, parents and kids always come up and ask about the robot which is a good conversation starter! As well, for Code Orange there is such a little amount of resources within out county that we always have to travel to San Diego or LA, so I say if you can work in your city most of the time, but do attend some outside your city. 
The only word of advise I’ll give is that you should attend every outreach opportunity if possible, big or small, profitable or not, during build season, competition season, summer, or off-season.
You never know who you will meet. A new mentor, a new sponsor, inspiring new kids, or something will happen which will indirectly positively impact your own team!
More than half of our sponsorship we have gotten came directly from the advise given.
Never turn down an opportunity to do anything, especially if they’re crazy enough to call and ask for you. My right toenails still hurt from a failed experiment at an outreach event 3 years ago, we’ve had to spend extra time and money to repair the robot after outreach events but right before offseasons, and we almost trotted out our team to a premier of Robocop on the last weekend of build season! Every single person you have a chance to meet matters. If they aren’t helping you, you’re helping them.
Make sure to plan a couple of events to demonstrate the robot and talk about the team to next year’s freshmen too. In addition to the events we’re invited to, my team shows off the robot during the 8th grade tour of the high school and gives a presentation to the 8th graders at each of the middle schools in our district. I’ve had one new recruit specifically tell me that he joined because he was impressed by our robot when we went to his middle school, and I suspect that that is the case for many more students as well.