Most fields are decent for a wheel chair and as said most have handicap parking (but remember that most parking is just spaces in a field). Another idea is to get a scooter. My wife had (has)a blown apart knee and did okay with the cheap "rental" scooter though got stuck in New England Mall's gravel. We have a few regulars that use their scooters all the time. If you go that route try to get a better one that will go "off road" some.
There is hansicapped parking in most parking lots but some fields have uneven ground and difficult travel in a wheelchair. I would not attempt entering a field when it opens as the crowds can be like the Oklahoma land rush as they enter. Wait a bit. The large parking field across Rte. 20 from May's does have handicapped parking and it is close to the street.