To us,Puerto Penasco isn't really Mexico--it's more like Arizona's beachfront. :B More gringos and that lifestyle than Mexico.
Having said that, for a first trip, it's better than nothing. We really like the interior cities of Mexico--Guanajuato, Morelia, Patzcuaro etc. (Don't go there for the heat!)
Our first RV trip was via San Carlos to Mazatlan then Puerto Vallarta. That was 12 years ago. Now we wander around the country for a month or so then spend 3 months in Zihuatanejo before slowly heading north.
For a first trip Rocky Point is fine, then maybe head to Keno Bay, and on to San Carlos and/or as far south as you feel comfortable. Our first few days was white knuckle stuff but we soon got used to it.
Don't let the nay-sayers put you off. Enjoy! It's a great country and the people are wonderful.
Check our
blog for all the "TERRIBLE AND DANGEROUS THINGS" we ran into along the way.
Also get a copy of Mike and Terri Church's book,
A Traveler's Guide to Mexican Campingb then go to their website for updates to the pages that interest you.
See you on the road somewhere.