Not really. I do warn you some of it needs some touch up work to make it fully beautiful again. With that in mind, I'd likely start listening to offers around the $250,000 range due to the large item-labeled vault, portal, and original owner being me. However, I really don't need it so I'll listen to anything really.
Since the bulk of the value you've put on the town lies in the vault, I would suggest converting all those chests to donation chests so potential buyers can make they're own assessment. For all we know, the chests could be empty and the town value wouldn't be nearly as high.
Also, as I said before, I really don't have a set price. I've been inactive for a bit so it's possibly property values continued to drop during that time. I wouldn't be too surprised.
I cannot over a lot of money like everyone else but I can promise that the town will be used and will flourish, not be lost. I love the way it looks and the atmosphere of the environment!