Temporary Insurance 28 days where?

[eduardoysla]

Hi folks,

I've just bought an RV-Bus converted from Massachusetts and I am going to drive it starting May 25th all the way across the U.S. to San Diego, via Dallas. And then all the way down Baja, México.

I will have it registered with South Dakota plates.

Is there's an insurance that covers U.S. and México for 28 days / 1 month?

If not, what is the cheapest option for the purpose in the U.S and in MX?