@Thomas,
Oh, yes, continue to dump ballast overboard, but if you do the quarter milers (run faster than your 5k pace for one quarter the WALK for two minutes) combined with the long hills and the fartleks you'll see better results than just long runs.
My favorites fartlek in Central Park is :
Start at 59th Street, go east nice and easy until you get to the bottom of Cat Hill,(1 mile).
Run as fast as you can up Cat Hill, cruise a little slower than normal to the corner where the roadway becomes straight, sprint (no, really.) sprint to Coach Fred's Statue (2 miles).
Trot along to recover until you get to the next left curve, (It's time to play LightPole Tag!!) pick a lightpole up ahead, a quarter mile or so, run fast to it, trot for three or four light poles, do it again, then trot a shorter length of roadway, pick a pole, go go go, (one more of those should bring you to the 102nd Street Crossover) run fast to the Police Kiosk (3 miles)then trot to the corner.
You have four good up hills on the West Side. Start by running pretty hard up to the top of this first one. Lollygag down the back side, then push hard up the next hill, that should get you to the north edge of the reservoir; take it easy but not too easy on the down side, then really run very very very hard up to top of next hill (try to make the hot dog vendor at the South Edge of the Reservoir look up) :-)
AH.
A nice long downhill past the theater, (about 4miles) try letting your brakes off and staying with the up tempo, but don't kill yourself.
Play Lightpole Tag on the long semi-flat section.
or
Do little short sprints, sprint two poles, mosey for one, sprint two, purl one, purl? No. wait. that's wrong.
Okay.
Now comes the little (yes it is too, little) up to the Tavern of the Green, run up to the top and then you've only got to stay at or a little faster then your 5K pace to the finish. 5.1 miles!
No steady pace! Mix it up the whole time. Run like there is something wrong with your auto-pilot speed control. Runners sometimes get in grooves, I know I do, that pace that just feels great, but it's seldom a pace that is really challenging.
Go for it.
Joe(god he does go on.)Nation