Garry,

There's no need to worry about driving in Orlando/Kissimmee area, it really is pretty easy. Roads tend to very wide, cars tend to drive slower on the interstate (you dont see many 80mph+ like in UK) and the automatic gearbox means you press-and-go. I actually really enjoy driving over there (except when you get jammed up on I4).

If undertaking is illegal in some circumstances (and it seems so) then most US drivers break the law on the interstate - most seem to pick a lane and stay in it and that's what I tend to do.

Graeme