A small generator (800kW);
A stiff brush on a broom handle, several gallons of bleach, a 5gln bucket and a garden hose (for cleaning the exterior);
A carpet remnant (8ft x 10ft is enough), to form the base for an outdoor patio;
Two solar fans, one forward one aft, mounted so that there is a constant ventilation even when the trailer is locked up;
A satellite dish (if you don’t already have one for the TV);
A case of MRE’s or other camping/survival foods, enough for a week or longer;
Three 5gln jugs/cans, dedicated to nothing but drinking water;
One large bottle of spiced rum;
Matches (you never have enough)...
800 kW would be larger that the largest trailer.