As with any cultural themes, the best field trips would be ones that actually take you to experience the culture. However, unless you have lots of money to travel to a Latin country, you will need to find other ways to experience the cultures.
-Many cities have cultural (Puerto Rican Festival, Cuban Festival, etc) festivals each year. If there is one near you, try to attend at least one day.
-Check your local museums for Hispanic Heritage displays.
-Look for activities in your area celebrating Hispanic Heritage Month (continues until October 15th)
-You can also choose a Latin country to research and then have a day/night celebrating that culture. Cook recipes from that country, create a replica of the flag and any traditional costumes, learn a traditional song and/or dance, etc. If you are part of a larger homeschooling group (or have a large family), each person/family could choose a different country and you could have a Hispanic Heritage Festival of your own.