I'm not confident or focused enough to paint in the midst of a lot of strangers, but painting outdoors is very liberating for me the way I most often approach it.
I usually do quick and small (6" x 10" up to about 9" x 12") watercolor sketches, perhaps 3 in an hour, working much more loosely than I do in my studio work. I'll often use a very soft and small squirrel mop for these (mine is an Isabey 3/0). Outdoors I find it much easier to "edit" the landscape that I see, selecting those elements that are important to emphasize while easily eliminating those that are distracting. Inside when I'm working from photos, I find it much more difficult to 'break through the photo plane' and enter the scene, and I tend to get bogged down in detail. But I do bring a camera with me when painting outside just in case...
A gasketed palette that minimizes mess and a small water jar with a lid can help:
http://www.dickblick.com/products/ma...roof-palettes/
I usually get by with either unstretched spiral pads of paper, Arches blocks around 9 x 12, or I'll tape some down to a piece of plywood I have that (barely) fits in my bag. But I do sometimes haul out a half-sheet stapled to gatorboard.
Doug is right: it should be fun. Good for the eye, and food for the soul.
Clay