Umm, I know that you can't have that much money left, but, where the truck is now, isn't that supposed to be where the RV is and the truck goes more to the right? And isn't that where the red building and little brick wall goes? Also, the buildings do look a lot like they do in COD and it is a close replica, other than the things I already said, this should play out really well.
To fix the z-fighting you need to nudge your objects by clicking down the left thumb-stick. For even greater control over the height of your objects, do the aforementioned method of nudging, but quickly hit the "A" button to release it mid-nudge. This will allow you to get rid of z-fighting with ease, as well as get pathways perfectly smooth.
You could try to replicate the mannicans by using street cones but you probably would only be able to make two mannicans. You could also use rails but they might be a bit big (used them once for a "large headless teddy-bear.").
Sadly it's impossible to really include the feel of nuketown without being able to get a M60 and just spray through walls until you kill someone.
You know this map would be great to play gametypes like: infection, ctf, slayer, team slayer, assualt, and perhaps headhunter (team). But just wondering. what gametypes can be played on this map?