An 8WT is fine.
Hard core muskies guys usually use a bigger rod, in part because they're throwing enormous flies. However, for smaller muskie flies, ie. under about 8 inches, you can get by with an 8WT.
Musky anglers are tight lipped about their spots and aren't likely to divulge them other than in the most general terms. In SEPA, in addition to Marsh Creek Lake, you have some muskies in some sections of the Delaware River, Schuylkill River, Lehigh River, Nockamixon, and a couple other spots. Go to the PFBC website and look up warm water stockings (historical by county) and you can find the lakes and river systems with muskies. They're all listed there.