I'm OK with Carpooling, but it looks like jsigone, GP and Cbad may be a full car unless you can get four people and four bikes in a Prius.
The route looks just about right. An option that does not change the route hardly at all is to get back on the Peters Cyn Trail at Barranca, which will bypass traffic signals at Alton, San Marino, San Carlo, Main and Michelson then dumps you back on Harvard before University.
As far as the Laguna Beach detour, I have only ridden it once. The ride up to the turn at Brodway, the car traffic was so thick that the cars were doing bike speed or slower. There was one guy in an SUV that was as thick as the traffic, but I guess I can handle that.
Start from the Irvine train station (15215 Barranca Pkwy, Irvine, CA 92618).
(L) on Barranca/Muirlands
(L) Los Alisos
(R) Vista del Lago
(L) La Paz (regroup on top of La Paz)
(R) El Toro/Santiago Canyon (regroup on top, about 2 miles from Cook's corner)
Coffee stop at Pete's Coffee and Tea (cnr. Portola and Culver) about 35 miles into the ride.
(L) on Culver (delete)
(R) Irvine Blvd (delete)
(R) Portola (backtrack)
(L) Crosswalk to Peters Canyon Wash Trail entrance (press the button)
(L) Peters Canyon Wash Trail
(R) San Diego Creek Bikeway(At Barranca)-Becomes Peters Canyon Trail (mi 40.2)
(L) Exit Peters Canyon Path (mi 42.3)
(R) Harvard (mi 42.3)
(R) Berkley Ave/E Peltason Dr
(R) Bonita Canyon
(L) Turtle Ridge (delete, we can start at the bottom of NPC, not have to deal with the slow light at Turtle Ridge, and have a continuous climb)
(L) Newport Coast (regroup on top just before Pelican Hill)
Coffee stop at the Crystal Cove Starbucks (7958 Pacific Coast Highway, Newport Beach, CA 92657) about 53 miles into the ride (and just about 1 mile after the turn on PCH - make a left on Crystal Heights(traffic light), then first right into shopping center)
(L) Laguna Canyon CA-133 (regroup at Laguna Canyon and Lake Forest Dr)
After Lake Forest Dr go to the next traffic light (Pavona St??) and very carefully make a left turn to stay on Laguna Canyon Rd.
Cross over I-405
(L) into the Irvine train station parking lot