I think there may be market. We are experienced Mexican RVers and have travelled to 27 Mexican states by ourselves and to all the places you mentioned. However we enjoy travelling with groups of like minded RVers looking for adventure and unique cultural experiences and specifically those that involve interaction with local peoples, food, culture and language. EG, staying on private lands as guests of a ranch, churches, missions etc. I would not be interested if just staying in campgrounds and being escorted from point to point. Im thinking more along the lines of local guides well versed in local history and culture. Local dinners of "comida tipica" etc. Although it would have to be english based to draw clients a high spanish component from day one may also find a market. In other words have a spanish immersion component to it. We wouldn't hesitate to spend money on something like that. Kind of an RV latin American version of a Rick Steves europe through the back door tour. Avoid the tourist traps and hit the gravel roads. We have been trapsing around europe for the last two months doing exactly that. I haven't spoken a lot of english in the last two months. Way fun...especially in an Arabic country. :)
Good luck with your idea. Keep us posted. Feel free to PM me.
John and Angela.