I have taken the liberty of porting Knox County and Challenge 1 to multiplayer, for the most part of playing with friends.
Both maps fully work and can be used in both single-player Sandbox or Multiplayer servers. Both maps use a separate lot id outside of the main map so can co-exist with the main map and can be spawned in if a region is added.
Spawn region for Knox County:
{ name = "Knox County, KY", file = "media/maps/KnoxCounty/spawnpoints.lua" }, MODID for Knox County: KnoxCounty
Spawn region for Challenge 1:
{ name = "Challenge Map #1 Hut in the Hills", file = "media/maps/ChallengeMap1/spawnpoints.lua" },
MODID for Challenge 1: ChallengeMap1
You can find both maps on the Steam Workshop here:
Knox County Multiplayer: http://steamcommunity.com/sharedfiles/filedetails/?id=669180988
Challenge Map #1: http://steamcommunity.com/sharedfiles/filedetails/?id=669189457
All credits as stated in both workshop files go to The Indie Stone. and their respective developers.