regular crashing?

You can send your logfiles to [email protected] after finding them via the instructions here: https://github.com/StrangeLoopGames/EcoIssues/wiki/Getting-the-Eco-server-and-client-log-files-for-local-world

That allows us to take a look. I'm not sure where the map size came from (guess you two play on the same server?), but the maximum supported size is 2.56 km² - so playing on a world of that size is unsupported.