I've become fascinated with the running of the large houses in England after discovering Downton Abby. As a result, I'm more interested in the early 20th century than Austen's time, but any information is welcome! Also, suggestions for further reading / study would be much appreciated.
Generally, yes. For your next read through of P&P, I'd suggest the Annotated Pride & Prejudice edited by David M. Shapard who goes into the microhistory of the novel such as this. He says:
the growth of [visiting these houses] was one part of the genearl growth of tourism in this period... Many homes were open to visitors, and in most cases the visitors simply needed to show up, without prior appointment. This is why the party (The Gardiner's and Lizzy) can decide to tour Pemberly at the last minute.