Not convinced about the gadgets, most of them use a lot less energy than either propulsion or heating -- even the things that use a lot of power when on (kettle, toaster, induction hob, electric oven) aren't on for very long, they shouldn't add up to more than a few kWh per day. Running a full wash/dry cycle on the washer/drier also took about 3kWh. So maybe all that together (with a wash/dry every day!) needs about 1h per day of generator running (6kWh) if there's no solar, which would burn about 2.5l of diesel.
In comparison I reckon a full day of normal cruising -- allowing for locks and moored boats -- typically uses 15kWh, which is several times more than "gadgets", and would need about 6l of diesel for the generator -- again, ignoring solar, which is only a couple of kWh/day typical at this time of year.
The biggest fuel use in winter would be heating; mine uses about 2l/hour when the CH boiler is on but this puts out 14kW (it runs in bursts), so in winter I'd expect this to be the biggest fuel user. But if you don't burn diesel you have to burn something else, and smokeless fuel isn't much cheaper -- if at all -- given how much heat goes up the flue from a stove.