Who says Monmouth County is the best for central jersey? It's alright, but can't compare to Somerset. Check out Montgomery HS and Ridge HS to see two of the best in the state. There are many a crappy HS in Monmouth County. Both places have good trails, although I prefer soil to sand at some of my parks.
are you serious? i tell you what monmouth county has, you say what somerset cty has.
beaches: from sandy hook down to manasquan. you've got your tourist place (belmar), your rich enclave (spring lake), and the community town (avon-by-the-sea). granted, you've got Asbury Park in there, and i can't argue too much excpet to say that it is getting better.
parks: holmdel park (jersey h.s. state meet course), thompson pk (where paul tergat and tegla laroupe have been spotted on more than one occasion), hartshorn (consistently rated one of the top mountain biking places in the country), manasquan reservior, allaire st. pk. just to start. all are kick ass places to run - and only alaire can be classified as "sandy".
schools: holmdel h.s. and rumson-fair haven are two of the best in n.j., for public schools. the freehold regional school district is pretty incredible - it serves over 10,000 students, and does a damn good job at it, especially with its programs for biological sciences, law, etc. aside from that, there is one of the best catholic schools in the state - christian brothers academy, and about a half-dozen other catholic schools.
running scene: tough to beat in n.j., and even around the country. you've got the shore a.c. which produces national level athletes. thousands of road races, including big ones such as the Sheehan race and the Spring Lake 5. the Freehold Area Running club has races almost every weekend. high school track is incredible in just about every discipline. check out the county records - insane!
the shore a.c. has a great xc series, and there are plenty of outdoor meets including the Holmdel international, which has seen stars like roger kingdom, butch reynolds, eamonn coughlin compete.
extras: bruce springsteen.