"Spring Vacation" is a tune left over from the "Imagination" era...at the time, it was called "Lay Down Burden", and was going to be a duet between Brian and Carl. When Carl and Audree got sick, Brian and Joe wrote a new song called "Lay Down Burden", and the original one went in the can. During the "TWGMTR" sessions, the tune was recut. Brian came up with the "Spring vacation" title and the "easy money, ain't life funny, what's it to ya, hallelujah" lyrics for the chorus, then gave it to Mike to supply new lyrics for the verses; that was their first collaboration in eons (well, I guess since 1995's ill fated attempt at a reunion). The other two Mike-Brian-Joe collaborations were of newer vintage, and written more-or-less from scratch. For "It's About Time", they worked with a rhythm track recorded by Jim Peterik and Larry Millas, and came up with a melody, vocal bass line and lyrics: the verses are mostly Mike's, the chorus mostly Brian's. "Beaches In Mind" just came up spontaneously during the sessions as a true "from scratch" collaboration.
Which explains why Beaches in Mind seems a bit underdeveloped to some. It just didn't get the time in the cooker it needed. I personally like all of those songs. I don't mind the "Fun in the Sun" references because this was a reunion album and, in that context, those songs were an appropriate look back to the band's early years. Not sure why people don't see this in the context of an album meant to coincide with a celebration of 50 years of the band.
Radio is well themed, if you look at it as a bit of a retrospective, and it's not like they don't let you know that's where it's going from the start. The first cut is called "Think about the days." Then it moves to "That's Why God Made the Radio," which I see as a look back to the youthful influences on the guys. Then we get a string of catchy little beachy songs meant to recall the early hits but couched a more reflective, nostalgic mode. But ultimately, just as the beach songs gave way to the introspective young adult reflections of Pet Sounds, Radio moves to the Life Suite numbers which put it all into the perspective of these men who are now older and in the autumn of life.
So, Mike's main contributions are in the area he prefers: Fun and sun songs about the beach. Brain kept the introspection to himself. That's pretty much the way it's always been, so.. no complaints from me.