Full Time Models (or those who are very acquainted with full time models),

How do y'all spend your free time in between gigs, especially when there are several days between shoots?

I've never been full-time on a professional level, but I have had consecutive months of being exceptionally booked up. Generally  I use time between shoots to indulge in my other hobbies, to look for shoot inspiration and to socialise. No different than if I had free time with any other job.

I never really had free time when actively modeling. I was either shooting, sleeping or driving hundreds of miles between cities.

Any free time I had was spent driving from one photographer's location, to another's location. That could take a full 10 hour day to do a drive between locations

I'm assuming you mean what am I doing work-wise between shoots (not what are my hobbies)?  I spend a lot of time marketing, answering emails, planning upcoming shoots, working on new looks, wardrobe, concepts, etc., exercising...  A model's work is never done!