route recommendations around 20-30 miles Sheffield area

[Dundonald]

Does anyone have any recommended routes that I can cycle that are
approximately 20-30 miles with some good hills ? Preferably mostly off
road? I live in Sheffield. I'm in practice for the C2C and as a
guide so you know what I currently do I cycle to work 2-3 times a week
using the trans penine trail which is mostly off road and has a good
selection of hills both ways. It's a 20 mile round trip using an old
Raleigh mountain bike but it's light and does the trick for me so
far. I've been doing this for the last 3 years.

Thanks.