Mick
As I've said in another post I've just swapped my Navman for a Pro-Nav which I bought off ebay.
It's virtually the same as you're qouting on the RoadPro.
You install the rig's length, width height etc. and works out the route.
I downloaded all the Caravan Club sites off the Club site and hey presto it gives you the route, and yes they have been better suited routes up to press.
You also don't get the dreaded do a u turn, it just diverts to a suitable route.
Hasn't given me any narrow roads up to press either, in fact on a recent trip to the Southport site, it took us right into the pitch, friends with their Tom Tom got a bit of wonky on in Southport.
Put it like this I'm well pleased overall.
Tom