Some of my darkest skies have been in remote areas of Mexico. We camped at Bahia de Los Angles about 10 years ago. The town generator would shut down at 10PM and there were no other towns of any size within hundreds of miles. I've seen some great dark skies down on the Pacific Coast of Oaxaca as well.
Mexico can be safe if done right. I have driven in Baja many times; and, traveled extensively on the Mainland via buses over the years. It is much like the USA in terms of diversity of landscape, culture, and crime. It has the highest volcano in North America @ 18,491', the oldest university on the continent, jungles, deserts, oak savannah, pine forests, big metropolitan cities, small villages, etc.. etc..
The big cities there are much like big cities here. Good and bad neighborhoods. There are good and bad states, and areas to travel as well. Keep out of the bad areas, don't associate with bad people, and don't wander around drunk at night and you will be fine. The old saying there goes, "Good roads bad people, bad roads good people."
I've driven though the Sierra de Juarez - the range just north of Sierra de San Pedro Martir. It was nice country with some old gold mining towns amongst the pine forests. The roads are dirt/gravel at best and choose your own adventure at other times. My Subaru Forrester did well down there; but, a 4x4 truck would do better. You need a tow strap, air compressor, shovel, tire patch kit, etc.. and know how to get your truck unstuck.
Traveling in Mexico is definitely an adventure; but, I've yet to be robbed, shot at, or had a gun pulled on me in Mexico. (All three of those things have happened to me in the USA though!)
BTW - I love the Baja wines. The L.A. Cetto Nebbiolo is very good for being a more mass produced wine you can find in the stores down there. There are plenty of other/better boutique wineries around. The wine country area is just east of Ensenada.
Mike, I have put your posada on my list of places to visit when/if I travel down there next. I have seen your site before. Anyone interested in further research/travel might check out the Baja Nomads forums. A lot of ex-pats on there and it was pretty active when I lived in that neck of the woods. Its a good way to get a good feel on what is going on and where.