I had a play with Bikehike last night and it looks very good. Downloaded the course to the PC (as a .tcx file) and then used Training centre to upload it to the 305, where it duly appeared.
All the course points I programmed in bikehike appeared in training centre. Havn't tried it yet with this route, but I have put course points on a local ride before using training centre (didn't realise it until I saw it in TC).
The whole process was made much easier by having the GPX trace from RossBD, so I just had to add my points.
Up to this point I had been following the navigation instructions from Frank Kinlan's web site, where I create a GPX route using the Marengo site and use GPS Babel to upload it to the 305. I know that works, so I think I'll have this weekends ride (Faffers 400) on the 305 as both a course (out & back seperately) and a route, just in case.
When it works (which it usually does without fault) I hardly have to look at the routesheet at all, however, I'll also have a laminated routesheet, a spare routesheet and colour photocopies of the relavent road atlas pages. I don't much care for getting lost!