Unless you are importing something into Mexico, no you do not need to "declare" anythingt since you are travelling with your personall items, you are actually importing the RV and the toad.
The RV is granted a 10 year permit and the vehicle 180 days, count the actual days and not 6 months, to import anything requieres a lenghty prosses and a mountain of paper, My wife used to export from the U.S. and import into Mexico, so no as a tourist you do not declare anything to import, if you have weapons, leave them in the US.
The only port of entry where some meat and meat containing products have been confiscated has been at Lukeville to Sonoyta on 85, South of Ajo as has been reported on this post.
navegator
