Some good reservoirs not to far in Passaic county that have everything from Walleye to Musky and everything in between... Just a short ride over the Sparta "Glen Road" toward Oak Ridge and you are there... Have to get your permits.. I never have - but always thought about it.... I think by far, your best all around fishing options.. For spring trout, you are not far from the Wallkill river they stock the crap out of it and if you can get off the beaten path, can really get into them and holdovers too, as well as possible natives... As others said - Lake Hopatcong has it all as well. Huge Channel Cats, bass, hybrid stripers, musky, walleye... Where are you coming from?
I live nearby in Andover and fishing largely depends on whether you have a boat or like to fish streams. If you have a boat Lake Aeroflex has salmon lake trout bass catfish and pickerel. Lake Iliff has some nice panfish esp crappie. Swartswood is nearby and is known for its walleye. To fish any of them you need an electric powered boat. Shore fishing is tough. Walkill, Pequest and Paulinskill are good trout streams during stocking but get pretty warm in June in the Sparta area. If you can get onto fox hollow lake there is great warm water fishing but its private. Best of luck and welcome to Sussex county. In my opinion the best place to live in the state.
In addition to all the good advice, Sparta Mountain WMA has some fishing ponds/small lakes as well. Most of the trout streams were covered except the Pequannock which is very close and the Rockaway. There are smaller wild trout streams as well in the area if that's your thing.