Hi Jaycee....it's nice that you want Miss Buddy to go out on such adventures.
One thing to keep in mind is that it would be somewhat dangerous to take a reptile out + about in the cold weather. A sweater can't keep her warm [ or any reptile ] because reptiles can't generate their own heat. A sweater/coat or blanket keeps a human or warm blooded animal warm because it keeps in our body heat and intensifies it. But cold blooded animals have no heat, so their body temp. would remain the same with a sweater on as without one. To travel anywhere in the winter [ should only be done for very important matters ] you would warm your car to room temp. [ about 75 or so is fine, no need to blast the heat ] so that you are comfy with a light shirt while driving. The beardie can be put in a sealed box for the ride and the temp. in the car will keep her comfy. If it's really cold out, just keep her home. You can also hold her next to your body under your coat....your body heat will warm her but then once in the car put her in the box or whatever you transport her in. Hand warmers can be used in the box but they can get very hot [ the Hot Hands brand ] and must be wrapped in newspaper to prevent burns.
But it's best to leave Miss Buddy home in the winter....she might even be brumating by then anyway.