An outro can be very nice indeed. But I personally dont like lonngggggg outro's. Just a quick one to show what we have achieved or something :)
You could also (which is much easier, keep in mind this is your first, dont mkae it to difficult for yourself) just make some triggers with radio messages from HQ telling the players they did well and have deserved a holiday.
Make a chopper or choppers come in to pick them up.......fade out to black once the choppers are airborn again with the players, and show plain white text with "mission accomplished" or something ;)
This is a very nice addition and wont require you to learn how to make intro's. :thumb
Its not how difficult you make something, pay attention to details. making some kind of extraction is always much more apreciated than just ending the mission (to me that seems like the mission maker was lazy, not willing to spend time at an ending).