If you usually have trouble with buses etc. don't pull all the stops out to use public transport - take a taxi if you can afford it or get someone to give you a lift.
If you haven't washed or changed your clothes for a month, there's no point in going out of your way to do it just for the hearing.
What you say on the day counts for a lot, so if you don't have a lot of paper evidence, don't panic, just tell it how it is.
If you don't cope well in the morning, it's good that you are going early, so they can see that you struggle.
It is daunting, having a hidden illness/disability but just remember to tell them how it is.
If they ask do you read books and you don't very often, say so.
Like a lot of us, you may well have to take it to tribunal. At least you are talking to people at an appeal. At medicals, you are effectively talking to a rude computer!