If you can give me more information I would be happy to give you some recommendations. How many people? What type of food? How much do you want to spend including tax and tip? Do you want a BYO?
In the Princeton area I can recommend Elements which is one of the best restaurants in the state. I haven’t been to Rat’s, Hamilton since the new chef came on board but it is a lovely venue. In Lambertville I like Hamilton’s Grill Room, Manon, or No. 9. All of the Lambertville restaurants are BYO.