Not sure about the Birmingham bit of the ride but when you get past Wolverhampton, head towards Madeley, down into Ironbridge Gorge, then take the B4380 towards Shrewsbury. There are quite a few hills and the bit through and just past Ironbridge is very picturesque.
If you wanted to make it particularly long and difficult, you could head towards Much Wenlock, take the B4371 to Chruch Stretton, you could either then head up the A49 to Shrewsbury (quite a busy and fast road - so I'd avoid it), or alternatively if you are feeling particularly psychotic, could head up The Burway (good luck), over the top of the Long Mynd and then head north to Shrewsbury through the lanes. I haven't done this part of the ride but you honestly won't come across much better scenery anywhere. It's quite breathtaking. However, this would constitute a SERIOUS ride, with alot of very testing hills.
Good luck and let me know what you decide.