Back in 2004, I traveled to Mexico and researched about visa requirements ahead of time. I went to the Mexican Consulate Downtown LA and believe me, it was the WORSE consulate experience I have ever had.
They are SO disorganized, the place is a mess, children crying, drunk people and the staff looked simply illiterate. And I am not bashing the Mexicans here (I'm Brazilian and they are my cousins), but their consulate to me looked like it was "The Day After Tomorrow" and everyone was getting a Visa to Mexico.
Oh, well. I was more worried about getting back to the US than entering in Mexico. Although they clearly say that RTD holder MUST have a visa, I took advantage of their mess and disorganization. I actually DID APPLY for the visa, they saaid they'd call me in 2 weeks to give me the approval or denial notice, but that was back in 04 and unless they are still processing my application, I don't think they will ever call. Do I need to say anything else?
So, I decided to enter Mexico with my NP, which does not require a visa, and reenter the US with my RTD. But at the Port of Entry in Mexico City Airport, I actually presented my RTD (because I wanted all records of my trip in my RTD, NOT in my NP) and they did not say a thing,. just let me in and said "Bienvenido".
Long story short: Do stress about getting your RTD to get back to the States, you dont want IO to bitch at anything when you are entering this country. Unless Mexico has drastically changed the service at its Consulates, don;t go there to apply for a visa, its easier to learn Salsa or Samba in 24 hours than to get something from there.