We would like to plan a family vacation for July 06 with teenagers ranging in age from 13 years to 20 years, male and female and 4 adult parents. Most of them love the outdoors and adventure. The 13 year old boy only loves rock music and his guitar. We have discussed Boston, Chincotaegue, VA, Rehoboth,DE and would be spending 5-7days. These would be great for the 4 adults and all the kids but not sure about how to please the music lover.Any advice would be great,

hmmm-but this begs the obvious answer: tell the 13 yr old to suck it up and have fun, and if he can't learn to enjoy something else in life besides "rock music and his guitar" he's going to have a sad life. 13 is too young to do the moody teen b.s. (and tell him if he can't have fun, pretend so he doesn't spoil the trip for the other humans who will be inhabiting his world for a short amount of time. (been there, done that, and it worked out fine...)

There's a big diff. b/w Boston and Chincotaegue, VA (never heard of it) or Rehobeth, for that matter. I don't see any theme here. Do you want city? beach?

In any group trip, there should be something for everyone at least part of the time. Maybe each of the attendees should pick a place they'd like to go and present it to the rest of the group with a sales pitch on why they'd like it.

Absent that, I can only add that the Jersey Shore has outdoors and some Bruce Springsteen history
http://www.beyondthepalace.com/newjersey/

The first thing I thought of when I read your post was that this is kind of short notice. Are you planning to camp or stay in a hotel? I'm just wondering whether reservations will be a problem at this point.

Although I like the Jersey Shore/ Springsteen idea, I will guess that the 13 yr. old isn't into that kind of rock. I'd try to please the majority of the group and yourself as you seem to be the chief planner.

Gosh, you are all over the map...

Are ya flying or driving? If you are driving, let the kid bring his guitar.

This may sound crazy but what about going to Cedar Point in Sandusky OH and then on to Cleveland to visit the Rock and Roll Hall of Fame. Cedar Point is definitely adventuresome and the hall of fame would be interesting for the entire family. There are many state parks, beaches, hiking, boating, etc.. in this area. Below is a good website to access if you're interested in this suggestion.
http://www.sanduskyohiocedarpoint.com/

Depending on where you are located, you could do a "roller coaster"/amusement park theme and do Kennywood and Hershy Park in PA as well. Haven't heard of teens who don't like amusement parks (have 2 of them myself).

If you do end up choosing Boston and finding lodging, you could satisfy all. Plenty of outdoor activities - kayaking, boating on Boston Harbor and the Islands, hiking, rock climbing, bicycling along Charles River Esplanade and other areas,
-and for the lover of rock/guitar/music you would have the Berkelely School of Music and Emerson College which might have some nice concerts or happenings that all could enjoy one afternoon or evening, and the Hard Rock Cafe for lunch or dinner if he likes memorabilia and plenty of places with live music from jazz to rock in Boston, Cambridge, Somerville area.
Google some of the following for info:
trustees.org for hiking, beaches, etc
bostonharborcruises.com
bostonislands.org
-also the Boston Duck Tours for something fun for all ages.

japw82-that was the first thing that came to my mind, too. Went to Cedar Point and RRHF as an adult and enjoyed both.