To stay out longer, you have to add more food and fuel. Most people don't stay out much longer than a three-day weekend in the winter. Beyond that, food and fuel get pretty heavy to tote. Planning your route is important for safe winter camping, the first rule being to tell someone where you are headed and when you'll return. Also, hiking on snowshoes with a full pack is hard work, and it pays to keep early trips short and simple.
Winter camping can be a leisurely affair.
Carrying a pack over hill and dale is great exercise, and you're going to generate some internal heat. It's not uncommon to see winter hikers with all their insulation layers stripped off and the sleeves on their long underwear rolled up, strolling through subzero woodlands. Hiking on snowshoes is fun and occasionally challenging. Sometimes, near the top of a mountain where winds can drift light snow bushes can hold up the snow cover, and send unwary snowshoers plunging in to the waist. Setting up a winter camp is a bit of an art form.