Yes Alaska is far from being unsafe, I went twice and I can not imagine going with a bunch of other people and not be able to stop whenever I want to admire the scenery, shorten or extend a stay if desire. Reason for me for a caravan is that I don't think I would venture off the main highways being scared to end up in a Dead End, or dead at the end! and I would miss some. Safety is sure one of the reason for me as I do not know exactly what to expect. But I am very tempted to try it alone and maybe tie up with someone I meet on the way down and stay on main roads for the first trip. I have been on many trips across USA, Canada and Europe and was never scared to a point to turn around, common sense prevail and I would probably do fine in Mexico as well.
I know Caravan Soleil does not cover the long stay in PV, this is explained in the brochure, you do not have to stay there and you do not have to return with them, which I would not anyway, once I know my where abouts, I am ok on my onw, especially to go back on a the main road.
Their tour is about 26 days from Texas to PV. I do not know how long they stay in one place at a time, this is not well defined, or at least I did not see it in the brochure nor did I saw it in other caravan, this seems to be a gray area. They do have presentation to explain everything so I could go and ask questions.
I would not mind an English speaking caravan but my wife is not fluent in english so it would make a long trip for her, beside bonjour and good morning exchanges with others. I plan on learning basic spanish before I go, I think it is just common sense for me.