Your other posts indicate that you use a wheelchair.
Will you be able to steer the boat without alterations being made to the tiller? There are very few hireboats which are disabled friendly. I have a bit of experience with narrowboat hires and my experience is that they have take a fair bit of clambering up and down to the tiller, into the main cabin, and back out again, and the boats are, well, narrow, as are internal passageways. Locks are not difficult but require a fair amount of effort to open and close - you are moving a couple of tons of wood and steel in the water. Some able bodied folk have difficulty both with the windlass and with moving the gates.
That said, I have a wheelchair bound friend who with her husband lives on an adapted boat and together with their son they manage quite well.
The towpaths around locks and the descent from most locks is quite steep.