Hello, I would deffo avoid CAR at all costs atm, having spoken to some Swiss who were there recently, it certainly seems like a wise idea to avoid it.
1. Crossing the Congo from either a. Uganda or b. Lubumbashi (s. DRC nr. Ndola, Zambia).
2. Across Sudan and Chad then either Niger or Nigeria
For the 1st option, look at my other post in the same topic (reverse direction) - http://www.horizonsunlimited.com/hub...-to-east-49659
Of the two routes in the DR Congo I have outlines, with a motorbike, DO IT FROM UGANDA. This is much better than overland from Zambia. I believe Peter and Kay Forward did some of the crossing in 2000 (though they went northwards to CAR. At the time, tension in CAR was O.K(ish), now, just don't risk it. http://www.horizonsunlimited.com/forwood/democra1.shtml
This will give you an insight to the border and the roads as far as Kisangani.
I am planning to do this route with my 18ton MAN chassis camper later this year following a trip in Libya, the Egyptian gilf kebir and Sudan. Chad, at the moment, is about as stable as it is going to get. There appears to be a thaw in the tension. I understand that Klaus Daerr did the reverse of this route a few years ago (when there was more tension in Chad), he went from N'Djamena to Khartoum after much hassel getting a Sudanese Visa.
As you are American, I am not too sure on the regulations on obtaining visas. I know that both the DR Congo and Sudan allow US Citizens in though you may experience hassels and delays in obtaining a visa for Sudan.
Good luck with the trip! IMO, you ought to do the Chad crossing. Fuel can be sparse at the best of times in DR Congo and there will no doubt be a hell of a lot of hassel there. Chad is an amazing place (not been yet though!) and the Tibetsi and the Endenni in the north are well worth a look if you are up to it.
After Chad, there are again, 2 options:
1. Exit via the Lake Chad route into Niger and then cross into Mali and Mauritania then up the old Spanish Road to Morocco through Western Sahara.
2. Exit Chad into Cameroon (briefly) then cross into Nigeria and travel along the Atlantic (Benin, Togo, Ghana, Burkina Faso, Mali, Senegal, Mauritania, W.Sahara, Morocco).
I think that option 2 is certainly better for you. The Lake Chad route and the crossing from Timbuto to Atar in Mari is very sandy and the distances are long with intermittent fuel. The Atlantic route is mostly tarmac (off piste there if you really want it though) and the distances are good, as is fuel.
Hope this helps!