Like most writers I rarely dream up completely new ideas.  I tend to steal them instead, it’s easier!  
When I was a student one of my friend’s really did have a downstairs cloakroom called The Travel Room covered in magazine cuttings just like grandma’s .  I also once saw a documentary about a house somewhere in The US that had a highly polished wooden slide from the landing down to the hall.  I wish I could remember where it was, it looked fantastic.  The idea of an enchanted painting that transports you to another place is not new, think Mary Poppins, and yes, my grandmother really did go on and on about her visit to Africa and had a painting of a summer scene over her fireplace.  It was one of the Lamorna Coves by Dame Laura Knight (with the boys skinny dipping in the harbour). I can’t put it up because of copyright so here’s a link. In fact, I wrote the whole book around that painting but had to change it to the Monet below at the eleventh hour because I baulked at the copyright agreement.