Edge gardening is so interesting! That's definitely a place where a landrace or even a grex or hybrid swarm would help -- selecting for the earliest and hardiest plants.

The closest I know of is the Heirloom Survivors Grex, but the original page is down.

https://web.archive.org/web/20250126122714/https://wildmountainseeds.com/product/heirloom-survivors-grex/

https://app.seedlinked.com/en-US/seeds/vegetables/Heirloom-Survivors-Grex-Tomato?id=5604&species_id=2