Having hired someone from New Jersey, the client understands you have to get to them and back. They hired you because of your expertise. Anyone certainly has the option to look in the yellow pages for local talent, but you never know what you are going to get. It is not your job to recommend they use local talent to save money, it is your job to do the job they hired you for.
If it was not in your original quote, I would send them an email saying, Looks like I left travel expenses out of my proposal. Sorry about that. I estimate it will take $750 for me to travel to your location and back home, plus $350 for hotel and meals. Will you be able to cover this?”
When we write proposals, we include + T&L at the end, but do not give an amount, since that cannot always be predicted.