One problem with diesel generators is the need to KEEP them loaded. Run too long under a light load and you stand a chance of
wet stacking the engine.
I have a 10KW diesel backup generator we use during power outages. For prolonged outages like the hurricane we just had I find myself searching for ways to keep it loaded. It will run my 3.5 ton package AC with the rest of the house but the outside temps during the outage were 65 degrees so we didn't need it. After I had the water heater warmed up and all the laundry done we had to resort to baking cookies. I would not want to search for ways to keep it loaded 24/7.
For an off grid house I would definitely look into solar with a backup generator. Most of the research I've done on this indicates it won't be cost effective if utility power is readily available. If it was going to cost 20K plus to connect to the grid I would rather spend that plus to stay off.