I really like the concept. I'd rather like to see it more detailed. You should consider making it high poly model in order to bake good normals. Besides high poly modeling would unleash your creativity levels. I highly recommend you to check some of the Gnomon's/Digital Tutors tutorials about environment modeling. Those video references are probably the best in the market and even the most experienced artists still check it. You could learn many things about environment modelling and, for the most important, many cool new tricks
. However, this looks quite good. Keep it up.