The elevation is on the second page of the "The Walk" tab on the website - check it out here: http://www.keswick2barrow.co.uk/thewalk.asp?ID=2
It's very obvious where you have to go once you get started - and of course, there's tons of folk around to help keep you straight if you get worried. It's almost all on road, with just a very short bit (maybe a quarter mile) on pathways.
I walked it with a hydra-pak on. They have a burger fry up at Mile 20, so you won't starve, but you probably won't want to stop for that if you're running it. You may want to bring your own food/gels to rely on.
I've walked this route before (in 2008 - before I started running) and it's brilliant. I'd love to do it again - if anyone needs a body to make up a team, I'm in!
The route is gently undulating - there's an elevation profile on the K2B website which can give you a pretty good idea of what you're getting into. The first 10 miles are reasonably flat, followed by (I think) three hills, some more mild than others. The worst part is the four+ miles of (albeit gentle) upgradient after mile 26...just after you've run the equivalent of a marathon, and pass the only pub on the route, you get to go steadily uphill! After that it's a downhill slog to Barrow, where you run through the streets (and start cursing every little curb)
Oh, and the scenery is gorgeous, especially the first 35 miles.
You guys should read about Terrry Fox and his Marathon of Hope. This guy, a cancer victim who lost one leg to cancer back in 1979, decided to run across Canada to raise money for cancer research at the rate of a marathon a day. He managed over 3,000 miles before succumbing to cancer, which had spread to his lungs. He had averaged 23.3 miles a day.