York House is located on London Road, Stony Stratford. A picture is worth a thousand words, so here is a location map with York House circled.
I intend to be there from noon-ish. The building is set back from the road (parking at front), but has a large sign indicating its presence, a worthwhile innovation I feel.
Useful landmark is the Peugeot dealership next door. York House is a large (3-story) neo-graeco building.
Indoor camping will involve camping indoors. This is cleared. What did you want to know? A room has been set aside for the purpose, but apart from that you're on your own... There is adequate room for spillover people and the fastidious, so I see no problem in that regard.