After about 20+ minutes of playing i felt like i had a grasp of the level more and started to enjoy it however i still got really really frustrated with lack of signs in certain spots.
This. This is not good.
More then anything else though, while the use of colour and lighting makes an old theme new and interesting, the problem still remains that it very difficult to tell exactly where you are in relation to the map. The only real distinguishing factor is each area's wooden building surrounding the cap, and when you're not in sight of it you very easily get lost and confused.
I've considered this a rule of thumb in regardless to the flow of a Team Fortress 2 map. Players should understand the basic purpose, layout, and location of the objective within the first round they play the map. This means that during the course of the first round played (which would include all three parts of 2x3 CP and PL maps), the player should know where he is in relation to the objective and how to get there. Extra paths, hidden defence points, and all other aspects of the map can be discovered and used later, but the basic layout and flow should be understood as quickly as possible.
So far, the biggest problem with Furnace is that it is very difficult to get your bearings when moving from each of the three main areas. In contrast, maps like gravelpit have very distinctive areas that can be easily navigated to and understood.
What there needs to be is something physically distinguishable to discern where you stand in the map, like some sort visually distinctive landmark. While signs can help direct players, it still won't help distinguish the difference between A, B and C.
Actually, taking in account for C, it is very easily identified because of the laser. Perhaps something else could help distinguish the other points, like a power station or maybe even an actual furnace or a dried creek bed.