Picard is changing lamps and is questioned by a doctor. The doctor responds, "There hasn't been an earthquake here in thirty years." This is set in August 1893, and according to the Virtual Museum of the City of San Francisco, on June 6, 1893, there was a "strong earthquake...and many men in downtown offices rushed to the streets." There were in fact dozens of earthquakes in the 30 years prior to 1893, including sizable earthquakes in 1892, 1890, 1889, 1888, 1885, 1883 (the strongest since 1868), and on with noticeable earthquakes nearly every year.
After Data and the crew have reunited, Mrs. Carmichael comes to their lodgings looking for her rent money. As Data has proven adept at "earning" money, and should have plenty to spare, the gang hoodwink Mrs. Carmichael with a hasty "audition" for their "play," when Data could have simply given her some money.
Dr Crusher tells Commander Ryker that the field generated by the "cane" can only be balanced for one person. Ryker decides this means if he travels back to rescue Captain Picard, only one of them could come back. But a few hours before, an entire away team returned successfully, even those who did not have physical contact with device. Even if only one person could enter the field at a time, Ryker could have returned to San Francisco, found Picard, activated the field to send Picard back, and allowed the field to dissipate before re-activating it to return himself.