My list of must haves are as follows:
-Camera equipment with all charging cables and a freshly emptied memory
-All travel documents and insurance info in duplicate put in 2 different places
-Freshly paid off Visa as well as cash (Canadian or USA depending on what is needed) as it it sucks if you find out their credit machine is broken!
-A thoroughly inspected and proper running bike. Better to swap out a set of
tires or a chain a little early than have to do it on the road.
-Clear and tinted visor and cleaning rags for them.
-Spray wash and a dedicated rag for parts like tank that might get scratched if left dirty too long
-rain gear
-walking shoes
-ear plugs
-maps
-basic repair stuff like a multi tool, duct tape, electrical tape and zip ties
-sunscreen, hand sanitizer, meds etc
I keep pretty much all of these things on the bike at all times, but I do have an ST1300 with a top box so I'm never at a loss for storage space!
One thing I recommend to anyone traveling ANYWHERE regardless of mode of transport, even on day trips is GRAVOL and IMODIUM! Even if you only take 1 tab of each, they might save your whole day! I've had a couple of each stashed in a small bottle on every bike I've ever had. In 22 years of riding I've only needed them once and I was sure glad I had them! I was at a rally and did NOT want to spend the day in and out of a port-a-potty! If you end up eating something contaminated on a long trip, miles from the nearest rest stop they can be invaluable!