I wouldn't recommend a stroller, let alone a wheelchair. On my recent tour there was a person in a wheelchair, they didn't go through the house and missed about half of the rest as a worker wheeled them in from the back. So, it is possible in a very bumpy way.
No & it's only open a few times a year. Tickets sell out quickly
Not really. The house has stairs inside and out. The walking paths often involve step downs. Wouldn't recommend with a wheel chair.
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