A post in the Touring and Expedition forum will probably be the best place for route planning and accomodation advice..
I've only taken short rides myself that I've managed to plan google maps or what have you..
As to which route, I'd say thats down to personal preference.. If you want to get there quickly and don't mind the traffic, go for main roads.. If you can take the time, go for more urban routes. Bound to be more rewarding!
Charity wise, justgiving.com are pretty good - I set up a page in 5 minutes with no problems.. Only trouble was the group I'm raising with want to do the Big Cheque Handover so couldn't use as it all goes direct to the charity..
Terry