Can I get a French long-stay visa after entering on a short-stay visa? [closed]

I am a USA national. My wife is a French national (children dual). We reside in the USA. My wife is a professor and has received a sabbatical. We will accompany my wife on her sabbatical. We intend to spend the first part in South Africa. We intend to be there for very nearly three months and then go to France. From what I have read, I am supposed to apply for my French long-stay visa (for spouse of French national) in my country of residence and within three months of arriving in France. This leaves a very narrow window in which to secure a visa at the consulate here in the USA.

Other information: We will be in France for ~4.5 months. (I would have the same issue if I were staying for 91 days). I am a software developer and will continue to work for my USA company while in France. I will have business in Spain (attending conference) during my stay in France. I may want to visit countries outside the Schengen area while staying in France (e.g. Morocco).

I have read what official resources there are about visas that are provided in English. I know there is more information in French but I do not read French well enough to navigate those resources.

So, is there any way I can either, apply for the long-stay visa while in South Africa or apply for it after I arrive in France (which would, by default, be on a short-stay visa)? Any other ideas? I would prefer to stay within proscribed procedures rather than taking any chances.