Mike, you really, really don't want legs - and the support legs for the peninsula can be set back as much as a foot from the edge if you use half inch ply deck. Three-quarter inch deck is even better.
How you build the pylons for the cantilevered supports can be basic. The top only needs to be 20-24" for a 30" wide deck.
Did you frame on 16" or 24" centers? if 16", then a pylon every other stud will be plenty.