You might want to check out
http://www.sunshineartist.com -- I understand they review shows. They also have lots of other tips about exibiting at outdoor art shows.
Otherwise you'd probably need to ask other regional artists and craft people which shows they do and why.
Of course, you could attend a bunch of shows yourself and know for sure which ones you want to be in next year. Around here the application process begins so early in the season you might be too late to participate in anything this summer anyway.