P8 isn't a trip for novices, especially past the first pitch. I've also seen people struggle on Idiot's Leap, even though there's a handline on it. All depends on their confidence / experience.
Yes, Carlswark via Gin entrance (Stoney Middleton) or Jug Holes (Matlock ) would be excellent, then there's Giant's Hole to the first pitch, Suicide Cave (Castleton), Mouldridge Mine at Pikehall, Hillocks Mine, (Monyash), you can go as far as you want, Ricklow Cave (Lathkill Dale), Lower Limepits Mine (Ecton), St. Bertram's Cave (Beeston Tor, Manifold Valley), Waterways Swallet down to The Gallery. (Blore, near Ilam.)
I'm sure that there are many, many others too Paul, all over the Peak.
Mel.