Mirror Lake is almost straight out west of Seaside Heights. Depending on where you are in new york mirror may be more than a day trip for you.

If you wanted a recommendation on a new jersey freshwater body i'd point you more toward Monksville Reservoir. At least Monksville has been stocked with walleye since 1988. I havent personally fished there so i cant speak for its shoreline access and you may need a small boat but even greenwood lake is a great place too which has NY access too.

Here is google maps link to monksville and NW of monksville you can see Greenwood Lake.
monksville nj - Google Maps