Don't, as I saw one man doing last week, drive your motorized wheelchair down the left lane of a residential street with a small child sitting on your lap.
The poor little thing looked terrified and I don't blame her. It would only take one parent pulling out of the drop off area in front of the school on that street without looking and they both would have been toast.
Offer to hold doors, help with stairs, etc etc, but if the person says they're fine, take them at their word and move on.