I would stick with RD if at all possible. Although if it was at a not so busy time, it may work. Perhaps the teen can use the mid-day pool/resort break to nap, that's what my DD16 did! We were there over President's week and found it manageable doing RD (or very close to it at least) and then mid-day break and we used FP+ at a different park later in the day. On our departure day we did AK early, but not RD just to do safari, then went to MK where we had our 3 FP+ and FP for lunch at BOG. Walking around MK that day, (we arrived around 10/10:30) was a madhouse. We were commenting to ourselves why hadn't we seen these crowds all week? Then it dawned on us we hadn't really been in the parks mid-day for the most part and defintiely not at MK mid-day. Since it was our departure day we didn't take a break that day, so we spent the whole day pretty much in MK until 4. SB times were ridiculously long, we used our time to do the lesser attractions we wouldn't have done (Stitch, Philharmagic, Carousel of Progress, People Mover) and then used our FP+'s. I would stick with RD if you are going at a busy time. MK to me, for the time of year we go, is definitely a RD or late night park unless you are using your FP+ or don't mind the waits. The others you could get away with not being there at RD. We did single rider lines at Epcot for TT and never waited more than 30 mins or so, RnRC at DHS single rider was less than 40 most times and Everest, single rider was always minimal. Re-reading my post, my overall comment would be for MK, stick to RD, the others, if you can utilize single rider you can make it work. Enjoy!!