Some users are reporting an issue with the Stardew Valley Expanded mod where they are unable to leave Grandpa’s Farm. This appears to be an issue with missing files in the mod.
Check for missing files and ensure that all files are installed correctly.
Delete the “Mods/Stardew Expanded” folder and then re-download and install the full SDV Expanded pack.
Deleting everything in the Mods folder, redownloading everything, and copying the mods across again.
Make sure you‘re not using the unofficial update for mods.