I am sorry to be a wet blanket, and this post will probably get a lot of you torqued. You are planning an expedition (even if you don't cross the border). A Rav4 is way too light for this kind of towing. Yes, I know that the V6 model is "rated" at 3500# pounds tow capacity. But here are some things to consider.
The dry weight of the 177 is 2400 pounds. Dry weight does not include the A/C, Microwave, Hotwater Heater, Battery, Propane Tank, Fridge. I have the 171 (lighter) and my true weight towing out of dealer was close to 2800 pounds. Add a few pots and pans, a good mattress, a few cans of beans and corn, a few gallons of spring water, my loaded weight is close o 3000#.
From the tow capacity of the vehicle, you have to subtract the weight of the load in the TV in order to compute the CGVW (Combined Gross Vehicle Weight). If your passengers are 300# that does not leave much for cargo in the TV before you are over weight.
Whenever you assess capacity, you should always allow reserve. I would suggest to never count on using more than 80# of all your ratings due to other issues, like having some tank liquid for brief times.
I know many of you tow with vehicles rated at 3500# and do fine. This is true, especially if you are only going a few hundred miles down the road to the family favorite campground.
I am apalled at how dealer sales people skew the truth and will hook a 7000# trailer on a Ford 150. I camped next to this family recently. He had to dump his 150 and get a 250 PowerStroke.
About going to Mexico. Lets say you do go South of the Border with a rig pushed to the limits and find yourself in need of transmission repair. You will not find a competent Toyota dealer on every street corner.
Please think twice about this kind of risk.