I can add rain gear to your list. When I left Washington it was 95 degrees and had been over 90 for a few days. I checked the weather for the trip and saw no possibility of rain. Then a thunderstorm from Hell showed up just as we entered Calgary, a city of 3 million I was told, during rush hour, and we instantly had 2 or 3 inches of water on the road and got pelted with rain and hail in bumper to bumper traffic. @KayTwo had got an early warning from @SundreSlingQueen that it was coming and we pulled over about an hour before it hit to gear up. Luckily for me, @Ross brought extra gear and loaned me a suit because I wasn't smart enough to throw in even one of the 7 or 8 sets of rain gear I own. I felt like an idiot and not just because the legs of my rain pants blew up with the wind and made me look like a miniature Michelin Man.
We got another decent shower coming out of the mountains at Banff and I still didn't have any rain gear! I had a good set of tools. Sara and I both had one of those neck things because Jared gave us each one within minutes of meeting (thanks brother). I had sunblock. I had a AAA card. But no freaking rain gear!
As an aside, when we did get to the airport about an hour and a half after Sara got in and she ran out to the Slings, I had a poncho for her from @Ross, @exharleyrider put his jacket around her shoulders, @KayTwo gave her a neck gaiter and tucked her into the passenger seat with his cockpit cover - and I had nothin'. In 31 seconds y'all outdid my 31 years of - whatever it was I'd been doing for 31 years. You made her feel special and I appreciate it! So don't leave home on any major trip without the ability to (attempt to) stay dry in an unexpected squall.