sounds like a great adventure. most important is that you already have spanish and a colombian wife who has given you some of her radar over the years. get a gopro camera to record it. i don't know central america, but i lived/worked in caribbean, north and southeast asia, and the mideast for 29 years, and owned/serviced cars overseas during my career. toyotas are everywhere but u.s. specs maybe sightly different, likely not enough to worry about. you can get good oil on the way, there are bitogers everywhere. if you have car trouble toyota dealers are kept to a high standard because locals with money use them and expect good results. how about choosing a theme maybe related to cars or with a corporate angle for your trip? i don't know...take a photo of every toyota dealership on the way? or something else that interests you to keep it fun. bring some small gifts to hand out to the nicely helpful folks who you will inevitably meet. i accumulate gently used swiss army mini knives on ebay for my current 3x/year, month long trips to southeast asia. also good are new $5 wm minitools, ballcaps with your favorite hometown sports team. protection against illness (international health and medevac insurance) and personal threats (bad guys and bad bugs) is vital. no guns, sadly, but a small baseball bat, sjambok, cosh, riding crop or short cossack whip (ebay), pepper or even bear spray (practice with it) are ok. having a trusted wingman along for at least part of the way would be nice too. enjoy!