you will definatley need bug spray and no you shouldn't take any thing but a shuttle bus for tourist or a taxi i mean it's way cheaper to take a bus like un quetzal but its way dangerous i remember i took the bus in guatemala city to antigua and right after i got off there was a guy on the bus that shot the driver and the bus wrecked and if you've ever been to guatemala before the hills are awful when you fly in to guatemala you don't see no flat land at all but i loved the hell out of guatemala be safe you won't wanna leave but definatley don't ride the city buses if your american you will be the only one on the bus it's a crazy feeling but have fun be safe