Hope you're having a great weekend! Before you make an offer at Campton, I would ask - have you visited the Paloma and Saville communities of Windemere and the Belmaison and Belvere communities at Gale Ranch to compare and contrast?
I would recommend that you get insight into what recent homes have sold for within that community. Also, quick sale homes have better incentives, as do the homes where upgrades have been pre-selected for you. I have also seen some builders offer better incentives on dirt lots where construction has not yet begun.
I am currently working with buyers for similar square footage home and am very close and up to date with information on these and other communities in Windemere. If you have your heart set on a Campton home as your dream home and want to discuss your approach, please give me a call at (925) 984-7671 (no obligation!).
The best way to approach the negotiation would be to have a Real Estate Professional negotiate for you and if you're not already working with one, I would be happy to give you a credit back at close of escrow (at New Home communities offering a Broker Co-op) if I represent you.