LAN is possible with hamachi, beware though as i tried it and it doesn't work, you can give it a shot if you want though (https://steamcommunity.com/sharedfiles/filedetails/?id=236489520)
and its also multiplayer.
Format your flash drive as a FAT32, your flash drive may have been set up as a NTFS format.
Be sure there's nothing important on that flash drive though!