We stayed @ The Hollywood Roosevelt for 3 nights back in 2021, and did a lot of footwork around the area. You are correct, Hollywood Boulevard is a bit dumpy in the glare of broad daylight. We didn't go out at night, as we are a bit old for "clubbing." We walked all the way down to the Sunset Strip and got some neat pics of Chateau Marmont and the Comedy Club. Even found the address of where 77 Sunset Strip used to be. The Walk of Fame is historic, as is Graumans. We had breakfast at Mel's Diner, which we enjoyed.
Perhaps our most memorable part of Hollywood (we've done this twice) is a trip up to Griffith Observatory at sunset to see all the lights come on across the LA Basin after dark. But this pretty much requires an overnight somewhere in the area.
And here's something that your Mom might like, even if it's a driveby visit. I recall a bit of discussion about this place on a thread here a couple of years ago.
https://www.facebook.com/DisneyMansion
You need to know that from Hollywood to DLR/DCA is a bit of a haul, and if you're driving in PM traffic, you could be looking at 2 hours. We've done the drive in the early AM (like 5:30) and managed to make rope drop @ DLR both times. Around 45-55 minutes, IIRC. Had we dawdled another 30 minutes, it would have been a 2 hour trip, judging from what I saw on Google maps.
We've driven the Pacific Coast Highway several times, and it is scenic. We've gone to Paridise Cove in Malibu, as that is where
The Rockford Files was filmed. Decent food at the restaurant.
As for how much time to allocate to Hollywood/LA vs DLR/DCA, I can't answer that. If/when we go back, we will include enough time for some of both.