Preserve half decent chassis 1999 D TD5 90? Drive or tuck away?

Greeting from sunny Leyburn in the Dales. Please don't be rude to me as clueless. Have managed to snaffle this vehicle at a not too eye watering price but want to do my best for her. Chassis is solid but plenty of surface rust. Have got really confused over the variety of DIY rust treatments (but not many for an old lady with a gammy shoulder) & funds don't stretch to taking apart. Am a tough old bird & would have considered pressure washing & steam cleaning myself in the Summer but no drying facilities. I'm assuming the sooner I do this the better though this is not the best time of year. Despite Googling, I can't find any commercial company up here in North Yorkshire
Has anyone had dealings with Rustbox in Pickhill or any suggestions.
Q No2. In view of horrible weather up here I'm considering tucking her away in a sealed dry container for a couple of months. Is this an awful idea?
Many thanks

I wouldn’t worry about containers, it won’t get wet underneath as such unless driven on wet roads, would seriously look into using fluid film, search it up in you tube it’s amazing stuff, prep work is needed though like using compressed air to get all the junk out of all the crevices ( there is loads on a defender ) also you can vacuum out the inside of the chassis and then pressure wash the underside, with care, and then fluid film when all dry