I cycled round the route recently and I wouldn't exactly describe it as hilly. The first 6 miles south to Coalport are either level or slightly downhill. Coalport to Ironbridge is level for a few miles and I suppose the remainder of the route back is occasionally up slight inclines or level.
I only have access to small maps too but I have managed to work out most of the route accurately apart from which exact path it takes though Telford Park. I could email you full details about the route and the terrain if you like as I have cycled round the route recently.