It doesn't really matter which 100 miles you do, since there's a huge variety on any 100 mile stretch you care to name. You'll get cliff paths, promenade walks, wooded areas, little towns and villages, etc, on any stretch of the SWCP. Public transport to and from Birmingham is no problem either, since every railway line and several major bus routes feed inland to the main line railway. If you use Cross Country trains, then your outward and return trips will be single journeys without the need to change. If you do the stretch that Chairman Bill outlines above, then you'll always remember the 'big-dipper' series of ups and downs on the final leg to Bude!