Let wheelchair users know about the steepness of your ramps (ADA guidelines specify reasonable grades), and if they may not see them at the main entrance.
Let folks who can handle a few stairs know how many they’ll have to deal with, and that there’s a railing to help. (Some people, like those who use canes or walkers, can handle a small set of stairs with a railing — and some wheelchair users have more upper body strength than I ever will.)
Some wheelchair users have no problem with ledges under a certain height — they can easily navigate a few inches of threshold — while others need completely flat surfaces to get around.
For restrooms to work for people with wheelchairs or walkers, they need to be able to fit the device inside with the door closed. Specifying how many of these are available helps for restroom break planning.
Knowing how far from the car to the venue is helpful. Also, wheelchair users often have a ramp attached to their vehicle and will need open space on the sides of their parking spot (no trees, bike parking, or signage blocking the ramp). Haven’t seen one of these modified vehicles before? They’re pretty cool.
Walking folks don’t always have to think about small inclines they navigate every day or what material they’re walking on, but a little hill or loose gravel can be a real problem for people using wheeled assistive devices. Imagine how you’d navigate your event space if you had to do it in a rolling office chair — this will help you see challenges you might otherwise never notice.