Why do you specifically say Tanzania??
Because you have too many hours for the greenhorn jobs, I'd also imagine you'd prefer a better QOL. Only thing you might be lacking is a little van time, which is odd for someone with your hours working in AK. Still worth a shot.
I also am (was) both American and British (now only British), can't afford to remain American, the only country in the world that makes you pay income tax even when you don't live there.
I didn't know many African counties reported your income to the US IRS....