I just uploaded a map to Roblox. This is my first attempt. Very time consuming. I imagine I will get much faster in the future (even then it may be too much time but I can't determine that yet).  I am a little concerned about what the game looks like when I play/view it versus when someone else views/plays it.  Roblox has lots of models and parts one can import into their map and it is not clear which ones are free (e.g., I imported about 12 palm trees, about 8 destructible pine trees, and several zombies 1-2 very aggressive while others hardly move at all? Let me know if you see the trees and zombies.  Also there should be a pistol in your starter pack (press 1 to activate pistol).  I also built a boat which was very difficult to configure cause the vehicle seat is very tricky for a noob - map does not have much water for the boat but I can change that as I revise...

Link:  http://www.roblox.com/item.aspx?id=178842666