Officially, there are still land border crossing restrictions in effect on the US-Mexico border until at least June 21, 2021.
https://mx.usembassy.gov/u-s-citizen...9-information/
Entry and Exit Requirements:
- Are U.S. citizens permitted to enter? [Yes]
- The United States and Mexico entered a joint initiative March 21, 2020, restricting non-essential travel along the U.S.-Mexico land border to prevent the spread of the COVID-19 virus. Non-essential travel includes travel that is considered tourism or recreational in nature. The restrictions are in place until at least June 21, 2021. Please see the Embassy’s fact sheet for more information.
- Travelers entering Mexico by land from Belize, Guatemala o the United States may be denied admission if the purpose of their visit is considered non-essential (
). Travelers should carry evidence of the essential nature of their visit and evidence of their resident status in Mexico, if applicable.
I've toured in Mexico, though not in northern Mexico. The summer is not the right time to go insofar as weather is concerned.