Hi - sorry to have been so long getting back to you on this - I didn't realize you had written to me. My boat has the 5' keel, not the deeper one. But, I was sailing a 34 last week with the deep keel and it sailed beautifully, I was quite impressed.
I don't think the 5'10" keel will be much of an issue in most of Florida, although you won't be able to do the ICW past Key Largo - it shallows to 5 feet from there to the bridge. After that, it deepens out.
Coming south on the ICW, there are a few spots that, at low tide, could cause you some problems, but by and large, it's not till you get closer to a seven foot draft that you'll be really restricted.
I'm currently in FL at the moment, heading north. Hope you get this email in less time than it took me to reply.

Wally

Hi Wally,

Being a sailor, at least I call myself one, with nothing to do in a Maine winter I joined Cruisers Forum this morning and ran smak into one of your replies, finding that you too own a 34 Dufour. Ours is a 1976 and seems in great shape, we just baught it last summer. We have friends in Fla and like bare boat sailing in the Caribbean. Nancy and I will retire in a few years. Very interested in your experiences relative to a 5' 10" keel in the waterway and around Fla in general. Also your take on the boat as you have apparently sailed her for a few or many years.

John Dunlay