Stay away from Mel Bay books ...and beware of teachers. They have a self-serving agenda in wanting you to take lessons from them (that is, to put money in their pocket), and...if they don't know what you want to learn, they will try to convince you that what you want to know isn't worth the effort and you should be learning what they know (unless you want to play classical or jazz, then teachers of are some utility, because most of them cut from the same pattern). If you want to sound unique then definitely stay away from any formal training (like the majority of blues guitarists do). Go the "self-taught" route instead.

You might want to start out on a clssical (read nylon stringed) guitar at first. The plastic strings are easier on a beginner's fingers and the fretboard is wider, but you are probably already used to crowding up your fingers on a narrow fretboard.

If you already play fiddle, you probably know as much about the basics as you need to know. Probably all you need are some diagrams to show you where to put your fingers to play certain chords, maybe a chart to show you what the notes are on the fretboard, what notes the strings are tuned to,and a friend who can show you a thing or two (just ask the 'Cat), and your ear...

Above all, don't take anyone's advice, including this advice, unless it agrees with your instincts. "Use the Force, Luke"......