I'm the wrong person to ask about hills as from up north in yorkshire and got into trouble in the past for saying something is flat only to have people telling me off later.
There is a hump back bridge on the course which can be a pain in the bum if you arn't in the right gear when you turn the corner on to it. If your local your going on to the A4444 for the first bit of the route which is mostly a up flat if that help's and your going on a sweet down hill through a town with a railway line in it for the last bit of the loop. Other than the A444 it's quite country roads and a nice little route.
What Daylight said above to me is the best way furward. If it's any help a few people off the threads go there normaly for openwater training in the summer month's and I've just moved to birmingham so local ish so if you are still worried about the course come next june time if you want I'm sure me and buttercup, evilpixie ect.... will be mucking about on the bike route at some point so can show you exactly what it's like. basically it's going to be fun so don't panic, get some training up and come next september your going to be skipping for the ice cream van at the end of this one like the rest of us.
I've done the boar a couple of times and had a good chat with the organiser's there is no cut off basically they they see you struggleing they might surggest you call it a day but in term's of times you will be ok. Been very inpressed with there set up and attertude and highly reconmend the race. Don't have a plan yet for next year but hopefully will be there. Only reason wasn't this year was with moving house.