A road map of Florida with turn by turn routing??

[Kiwi]

Hi!
I'm on the lookout for a routable map of Florida roads as I'm planning a trip there later in the year and will be doing quite a bit of driving. I have downloaded Florida Topo, Ibycus USA 2.1, SE USA and none of these seem to have routing support (at least in MapSource).
Am I doing something wrong or is there a routable map of FL roads around somewhere? 
Thanks!!

[Kiwi]

Thanks for the link! I must say, anyway, that as far as auto routable maps go, they're pretty lousy! 
Many of the nodes are disconnected and drawing even the simplest routes becomes a very time-consuming effort.

I have therefore downloaded MapEdit and am trying to modify (correct) the maps, but find that once I have finally exported the files back into .img format I have now completely lost all "auto-routability"..   

SO: New question is where can I find a MapEdit tutorial for modifying maps?

Thanks again!