Places to Cross Country Ski near Philly?

OK, REI had a garage sale this past weekend, and I scored some discontinued XC skis.  Haven't skied since high school, and that was only a few times, and downhill.  Never XC before, so I'm looking to learn, and hopefully get some good cross training in this winter.

Searching the interwebz, I've found that most PA state parks allow for XC skiing when conditions permit, but anything with any maintained trails is pretty far north of me (Delaware county)

So for now I'm planning on going to a local park to start falling down, and then try to fall less.  Do people get out on the MUP along the drives, or SRT when there's enough snow?  Realizing it's a different set of muscles, how do the mileages compare between running and skiing?  In other words, what's equivalent to a 5 mile run while skiing?  Seems you're a bit faster on skis, but also working the upper body more.

Now all we need is some snow in Philly...