Not fitting Criteria

I already have PIP, but have recently deteriorated so I did what they asked, and told them. I've now received a New Claim Form (50 pages long), to complete. BUT, regarding the Mobility section, the Questions don't really fit my criteria. I am only able to go out of the house with someone, for support. I can walk but only short distances. I need advice, because at my previous assessment, I was asked about planning a route. I have been able to read maps since I was a small child, I used to drive so I understand road signs and directional signs. How can I approach the questions when its the Physical Walking that is my problem, not the route.?
Help please? Thanks.