That all sounds great but I'd rather have an over-spec alternator than have to monitor alternator temperatures personally, or chance losing charging capacity due to an overload. A 60A fuse only means that the wiring is expected to handle more than 60A, and the load is expected to draw less; it doesn't really indicate actual load. I would expect 40A out, same voltage in and out, would draw 42A to 44A for a reasonably efficient regulator.

I think the inverter power being derated by Toyota from 400W (in park) to 100W (in drive) is indicative of how much (or little) power is available from the alternator. I agree, in a lot of cases the stock alternator is probably fine for this application. I'm still going to hold out for the DC Power alternator, just because I want the extra capacity, and may add more loads later.

Thanks for sharing your solution. It sounds very useful for a lot of users.