There are laundry detergent sheets that you could buy if you're worried about liquid limits. I got some at a local travel / luggage store in their accessory stand. Amazon also has some.
I mostly take what you expect: a portable charger, calling cards (assuming I have to call internationally), credit card and cash, essentials (makeup/hygiene care/hair products/etc), a good pair of sneakers and my favorite heels, etc.
If you're going somewhere with the intent of swimming then a full body swimsuit is necessary in my books. Regardless of how much sunscreen I use I will end up like a tomato without one. This is the one I bought. I got my first one last summer and got six uses out of it with no complaints. I'll probably buy another one this year to be on the safe side but the quality is great (especially for the price). I think it's cute, a lot cuter than many "regular" suits, and it's definitely comfortable.
Other useful items I try to bring:
Soap Sheets: They dissolve with a bit of water and come in handy for laundry. No TSA worries here!
A bra stash: I would've never personally bought this for myself, at least not initially, but it was a brilliant gift from my mother when I went away to school. There's a slew of reasons why you may not want to carry a purse or wallet. This will be your saving grace. It's not like the majority of us haven't done this anyway....
Compression Socks: Long flights will typically cause your extremities to swell up but no more! This is a serious, serious lifesaver on long trips. I learned this the hard way on my flight to Japan.
Probiotics: I know that sounds crazy. I KNOW. However, I've never gotten sick from a flight OR experienced much jetleg while having these in rotation five days prior to flying, during, and after. Worth it.
Diva Cup: You should be using these anyway during menstruation, but if you aren't, then while traveling is a great way to start. You won't have to worry about pads or tampons anymore. It's also a lot healthier and easier!
Wow, that looks like an incredible route!
I have always kept my bike in the hotel room, never has it been an issue. Although hauling it up narrow stairs to a 5th floor room in Crete was a challenge!
I think that packing two sets of cycling clothing is a good idea. I always bring a rubber stopper and travel laundry detergent (such as this stuff) so that I can always clean my clothes in the sink, even if there's no laundry facility.
For a bike lock, I would recommend one of the Abus folding locks. Some of the smaller options like this one are quite light.
I would also bring some spare quick links in your parts kit, in case you need to repair a broken chain. A few zip ties are also a good thing to have, just for quick fixes to get you to the next bike shop.
Wishing you the best of luck!
I used these to wash my laundry in the sink/bathtub while travelling and it was really handy! It’s quite small, will fit in the palm of your hand