For my pre-travel brochures I put an intro./thank you page, what to expect when they arrive in Mexico page, what to do before you go ie: credit cards, cell phones, they shouldn't need to convert dollars to pesos page, a page about the local info. like weather, time, etc, a page about travel info. like passports, luggage info. and a page with items not to forget.
I also think it depends if you plan on also doing a brochure or newsletter when you arrive in Mexico as well. Because if you only plan on doing one, you may want to include info. for wedding day timeline, any group activities, etc.