Hey there! My husband and I started in Antigua and then went to Lake Atitlan in March 2022 and had an AMAZING time! We traveled with carry-ons and a small laptop backpack each. We each used a "Cotopaxi Allpa 35L Travel Pack" for our 10-day trip and it was perfect. We used compression packing cubes from Eagle Creek. You will spot plenty of people walking the streets with travel packs. You will also spot people unloading small suitcases at some of the more "luxury" hotels. The street are cobblestone in Antigua so rolling a suitcase very far would be not ideal. However, we easily took tuk tuks and Ubers over walking between stays when transporting our bags. I don't see an issue either boarding the boats of Lake A with roller bags. Your ride will take you straight to La Fortuna and you can easily get off with either a backpack or a small wheelie suitcase. I felt peace of mind having a small travel lock on my bag with my laptop but overall felt extremely safe in Guatemala. You can find ATMs throughout the city and can easily pay with card in most places except maybe the local markets. As far as other things to pack, you may want some bug spray or anti-itch cream for any bug bites...go into La Fortuna knowing it is AMAZINGGGGG and also situated in the jungle. Our bathroom for example was completely outside where other critters make their homes :) In Antigua, I absolutely have to recommend the private room with Volcano view at Ojala!!! The staff there can't be beat! The breakfast and bar and food available was delicious and it was truly magical. So close to everything for wakling around and just truly we became dear friends with the amazing staff...would go back and spend our whole time just at Ojala in a heart beat! We also loved getting a bite and drinks at Antigua Brewing Company and seeing the volcano view from the roof top bar. Stunning! Have a blast!