One lightweight option I’ve found worthwhile is carrying a pair of synthetic camp socks dedicated just for sleeping-helpful when boots won’t dry overnight and you need to protect your sleep system from moisture. For faster drying, wringing out boots/insoles as much as possible at camp, then stuffing with highly absorbent pack towels (wrung and swapped out if needed) works better than clothes, and the towel can be air-dried more easily afterward.
Regarding heated rocks and chemical packs: both can be risky. Direct heat (especially from rocks that aren’t just warm) can delaminate midsole glues and damage waterproof membranes, as supported by gear manufacturer warnings and anecdotal field reports. Chemical warmers are safer temperature-wise but often ineffective in drawing out substantial moisture in high-humidity environments, and represent added weight/trash.
Ultimately, given the limits of cold, damp backcountry environments, the best compromise tends toward managing comfort (dry socks, camp shoes, careful sleep system protection) rather than reliably drying boots overnight. If anyone’s encountered a controlled study comparing field methods, I’d be interested too-most available info is experiential or manufacturer guidance.