This review is especially helpful for those who have or use the following: Powerchair
This section of the Trans Pennine goes from Rother Valley Country Park and Killamarsh (old railway station) in either direction, but we did the leg to Renishaw and Poolsbrook Country Park at Staveley. Provided you get the right access point, the old railway track is a good surface and fairly flat. I am guessing the whole trail is good but the crucial point is to find an accessible path up to it. On this leg you can go up a steepish but good surface from Rother Valley park (half way round) or off Station Road, Killamarsh. Do not use Forge Lane but go under the bridge and turn left towards an industrial estate and you can park next to the trail.
Transport & Parking
You probably need a car although there are buses to Killamarsh.
Provided you research a good access point to the trail, once on the old railway track it is very good surface and gradients are gradual, much of it is flat.
The only accessible toilet near this section of the trail is at Rother Valley Country Park visitor centre.