You can walk to the parks (about 10 minute walk), take the water taxi or take a shuttle bus. We usually walk, but if the water taxi is there when we're walking by, we save the steps. It is very convenient to get back and forth to the parks from all three of the Universal on-site hotels. The shortest walk is from the Hard Rock Hotel. The longest walk is from Portifino Bay (about 15 minutes or so).
All very easy. There is a snack bar, but I've not eaten there so I can't comment on the food or prices.