Where a greatest percentage of heat is lost is up, If possible look into
foam roofing, R 35 is minimum R 50 best for your area. You will have
to figure an extension for the sides , but look into it , see if
trailers do it. I take it you have cheap hydro elec. .05 kwh . If
not consider gas. im 0.125 kwh , double the cost of gas. For most US
elec is double that of gas. Whatever your upgrades you will will
benefit and yes more insulation is better, as standards in place are
obsolete and far from optimum. The US is cheap energy compared to most
of the world, But its going up.