Our 2 older kids, (13 and 11) have been to Disney a lot, probably 15 times. (we live within driving distance so season passes were the way to go) Our youngest (7) hasn't been much since the older 2 kids have gotten into sports and weekend games now largely are a barrier to driving there.

My older 2 kids, they're into bigger rides, probably like your 15 year old. They'd rather go to Knottsberry Farm which is close to Disney, bigger rides, and significantly less cost. Youngest kid wants to go to Disneyland.

So my wife took the older ones to Knotts (back injury for me from doing big roller coasters) and I took the younger one to Disney. So we essentially saved $360 by 3 people going to the place the older kids wanted to go (Knotts) so they got what they wanted, the littlest still got to go to Disney.

Since the parks are close it was easy to do.