While Rick Steves suggests spending a night or two prior to the start of your tour in whatever city it may begin to better acclimate yourself, I've never really been one to follow suggestions. Instead, prior to my arrival in Venice, I enjoyed several days in Cornwall & London.
In Cornwall, I stayed at the Jamaica Inn, built in the late 1700s & immortalized as a novel by Daphne du Maurier & film by Alfred Hitchcock (and later others). For those interested in exploring this part of southern England, I found it an ideal location to stage visits to places like Tintagel (legendary birthplace of King Arthur), Slaughter Bridge (the location near his final battle with his bastard son), Dozmary Pool (home to the Lady of the Lake), the Museum of Witchcraft & Magic, Dingles Fairground Heritage Center & other area attractions.
I flew into Cornwall's Newquay Airport & from there, left for London from Gatwick. In London, I chose less interesting lodgings, settling for a Hampton Inn, centrally located in their Waterloo district, very close to the train station & Old Vic, & about a mile away from the West End, which made it ideal for me, as I was there to see some theater. I couldn't get tickets to the Potter play, but I was quite happy with The Woman in Black (as are many others, as it's been running for 27 years), Peter Pan Goes Wrong (absolutely hilarious) & David Bowie's Lazarus. I also caught the final night of the London Blues Fest, which featured Jeff Beck & Van Morrison.
But I'd never been to London before, so I naturally had to do all of the touristy stuff, from things that satisfied my Disney fanboy nature (Regents Park for its connection to 101 Dalmations & St. Paul's Cathedral for its part in Mary Poppins), to the Dickens Museum, Sherlock Holmes Museum, Star Wars scenes & Spirit of London dark ride at Madame Tussauds, Tate Modern, V&A Records & Rebels exhibition on '60s rock & its role in the protest movement of the era, Peter Pan in Kensington Garden, Great Ormond Street Hospital, & countless other places.
My most interesting culinary experience in London was definitely at Dans Le Noir. If you have ever seen the film About Time, with Rachel McAdams, it's the restaurant at the beginning of the film, where they are served in complete darkness. You do not know what you are served until after you have eaten & the wait staff is blind. It's a jarring but fascinating experience.
Even in late October, though I understand it can vary constantly, I only saw rain a single day & even then it was rather brief. I'll happily answer questions about any of the above places for anyone who might be interested.
On Halloween, I made my way to Stansted Airport to Venice & though confused by Venice's many narrow, winding & dead-end streets, I eventually found the tour's first hotel, the Pensione Guerrato. Located steps from the Rialto Bridge & the market, it is tucked down an alley, affording a measure of quiet, at least for those guests who are fortunate enough to be on a side facing away from the clamor of the market.
With our tour meeting not scheduled until 4 pm, I set about to begin my adventure on my own, eager to see some of Venice's
most beloved landmarks, notably The Disney Store & Hard Rock Cafe. Having got those out of my system, I then went off in search of a building that served as the exterior of a library in Indiana Jones & the Last Crusade ("X marks the spot"), & is now hosting a small Leonardo da Vinci museum. After enjoying the exhibit (& dumbly buying a lighter, thinking it was a magnet), I enjoyed a Casanova beverage at the famous Cafe Florian overlooking Doge's Palace & made my way back to the hotel.