Discover Baja is processing 10-year motorhome TIPs for DBTC members. You can fill out the application to get started. Please allow them at least three weeks for processing.
I like Discover Baja for my vehicle, trailer, motorcycle insurance, and their extensive resources and highly recommend membership.
Alternately you can go online to Banjercito to apply for the permit. You will need to start the process about two weeks before heading to Baja, as you will need to allow time for processing and for the permit to be sent to you in the mail. You cannot process the paperwork more than 60 days before heading into Mexico.
Get more details at: http://www.discoverbaja.com/go/motorhome-temporary-import-permits/