This was one of those puzzles that we literally did together. At the same time. I held the iPad Mini, and Frannie looked over my shoulder and called out answers when she knew them. The puzzles often fly by when we do it that way, and today was no exception.
We enjoyed the APPENDAGE (35A: Wing, e.g. ... or a hint to answering 17-, 23-, 49-, and 56- across) theme. The best, probably, was ESTREETBANDAGE (49A: First-aid supply for Springsteen?), but SCOTLANDYARDAGE (17A: Distance at St. Andrews golf course?) was right up there.
Seemed to play a little easy (even without the double-solve it would have, I think), with the exception of some very tough short stuff. I'm guessing that the 20A: Org. of which 18 U.S. presidents have been members (BSA) is not the "Boston Society of Architects." Wait a minute... just now, as I write this, the Boy Scouts of America spring to mind. Hmm... interesting. I'll have to look it up to see which 18 were scouts. Let's see if the same sudden realization works for ANSA (64A: Vase handle) or OMB (38A: White House fiscal grp.). Nope. I had never heard of NAT (23D: Writer Hentoff), or GARN (37D: Only U.S. senator with a unit of measure named after him), and didn't remember TEK (31D: William Shatner's sci-fi drug) or ENA (55A: Aunt in Bambi). I might have heard both, but the original Star Trek and Bambi are both fading memories.
I enjoyed the clue for LSD (10D: Trip inits.), and the one for TOES (13D: Low digits).
It was a decent enough theme, and I liked seeing things like NAMATH, OBERLIN, MACBETH and STAGGER, but there's kind of a lot of weird stuff. Meh. I guess it's fine.