When I began to attempt the dream interpretation, after I knew the problem that the subject was having, I took into consideration the physical areas covered by the dream. They seemed clear to me.
The ureters and urethra are long (relatively) and narrow tubular parts; much like a road or driveway, connected to the kidneys and the bladder, forming the urinary tract.
The presence of debris on the road and the driveway indicates infection of the urinary tract to me.
The tall phallic mushrooms are obvious, and stand for a male, which the subject was.
The kidneys are located in the rear of the body; hence the "back door" of the house. A house in most dreams will refer to the body (or the life of the person dreaming).