Hacienda/Glendora/Vincent?  Tough to keep those street names clear, ain't it?
If you were born in 1957, then by the time you were 5 that taco place was gone and the Old Center was in decline, thanks primarily to the growing competition from the Plaza and its environs.
The Orange Julius?  I don't recall one being down La Puente way, but there was an Orange Julius in my neck of the woods on Glendora/Vincent at Vine.  I'll bet your mother wasn't too happy when you dropped that glass.  Yuck, what a sticky and broken-glass mess!
Memories in general?  I love wandering through my databanks, and I've been blessed/cursed with a sizable "hard drive."  Typical for a writer though, eh?
So you remember the Green Burrito?  Great food, and they were open 'til 3:00 a.m.  By the time I was 16 (1966) and able to drive, my friends and I would occasionally get the late-night "craving" to go there.  However, the later it got, the more we gringos were reluctant to venture into La Puente.  I can remember that when we did muster the courage, we'd stack close together at the order window...and then once we got our food we raced back to West Covina.
Were our fears justified?  We thought so.  Fortunately, nothing ever happened...although there were a few occasions when we were downright scared.
The Green Burrito was on Glendora/Hacienda, a block or so south of the Sav-On ("Sav-On!  Save-On!  Join the Sav-On hit parade, it's fun to serve yourself and save at Sav-On drug stores, Sav-On drug stores...SAV-ON!").
And just north of the place was Gigi Burgers.  Remember that joint?  They made fantastic slushes, better than those at the Foster's Freeze that was a block or so south of that Orange Julius.  But their big seller was their hamburgers, which in 1960-61 were 15 cents!  My Little League coach would take the team to Gigi Burgers after each game we won.
Now let's see.  You grew up near Puente Ave. and Francisquito.  So that probably means that your family shopped at Thriftimart ("Whatever you put your shopping cart, you save and save at Thriftimart").  I can still see that big red "T."
On the parking lot across from Thriftimart and on Francisquito was The Bahooka -- a quasi-polynesian restaurant.  It was still there in '73-'75, along with its sister location in Temple City.  But the Franciscquito location was much better.
Do you remember Hartland Hospital?  It was on Francisquito east of Puente Ave.  And a block or two east of the hospital and on the opposite side of the street was Winchell's Donuts.  Word was that if it was 3:00 a.m. in that area and you needed a cop, just go to Winchell's.  ha ha ha
Then again, in the late '60s to early '70s, if you got the donut munchies at that hour, the last place you wanted to go to was Winchell's, if you get my drift.
Heading west on Francisquito from Hartland Hospital, near the freeway underpass was a Der Weinerschnitzel (today the chain is just called Weinerschnitzel).  And not far from that place was an In-N-Out, the other In-N-Out being on San Bernardino Road near the hardware/lumber store Pick's.  Both In-N-Out's were open 'til3:00 a.m., and at that time the Der Weinerschnitzel also stayed open 'til that late hour, trying to grab the bar crowd.
"Der," as we called it, never had any crime problems, and the cops usually didn't hang out there at night.  But In-N-Out?  Different story.  Both locations were frequent targets, so In-N-Out offered the local cops free food and drinks if they would stay in the parking lot to eat their stuff.
I knew several of the kids who worked at the San Berdu Rd. location, and sometimes I'd just hang out there at2:30 a.m. to watch the "show."  Yep, my friend reported and I saw for myself how the cops would be shooting fish in a barrel.  Some poor drunk shmuck would maneuver through the drive-thru and slobber his order.  The guy (in those days, girls didn't work at In-N-Out) would immediately realize that he had a boozer on his hands, so after taking the order he'd go to another window and flash the cops a thumbs-up sign.
The unsuspecting sot would pay for his food and then drive out...only to be lit up by the cops the minute he got onto the street.  Many a DUI was issued at that In-N-Out location.
Was that fair to the customers?  Probably not.  But the kids working that store felt safe with the cops around, and they didn't want to jeopardize that.  [NOTE:  Several of those boys occasionally had scrapes with the law.  Nothing major, mainly traffic violations and suspected DUI.  But they'd developed relationships with the officers, so they got off with a stern warning.  Ah, politics.]
Yes, I have a junk brain that's stuffed with memories.  However, we all do.  It's just that some folks don't think they do.  So here's a little trick for you, in case, like me, you enjoy reminiscing.
Write down whatever you can remember.  Doesn't have to be perfect prose.  Just fragments, if you will, of what comes to mind at that moment. And don't worry about spelling, punctuation, or the rest.  Simply jot down whatever you recall. 
Then stuff what you've written (handwritten, on a typewriter, or a printout from your computer) in a cubby or drawer at your desk and leave it for several days.  When you come back to your tract and scan it, you'll find more and more memories surfacing.  Add those to your manuscript, and then repeat.
It works.  But alas, I can't take credit for this trick.  It comes from Mark Twain.
However, I have another trick that I've used, and it's wonderfully effective, too.
Close your eyes, think back to any place you'd been in your past, and "walk the streets."  Imagine that you are, for example, back in 1964 when you were 7.  Where'd you go?  What did you see?  What did you do?  Whom did you meet?  Where did you shop?  What movie theatre did you attend?  And so on.
It's a version of "remote viewing," but here you're going into yesterday, not now.  You might call it "memory meditation."  But whatever the label, it also works...and it's great fun.
And for me, when I do this kind of time travel, I try to remember not just the sights and sounds but more importantly the smells (olfactory memory is the most potent of all).
I remember the Center Market in the Old Center in West Covina.  Very small store (and a few doors down from the Western Auto).  They had an equally small butcher section in the back.  But what always comes to mind for me is the aroma of the place.  It smelled like Sonny Boy, that juice concentrate ("Sonny Boy, Sonny Boy, Makes 3 quarts of drinking joy!  Needs no sugar, tastes just right!  Have some Sonny Boy tonight!  Sonny Boy, Sonny Boy, bring some home today!  Giddy-up giddy-up giddy-up go, get Sonny Boy!")
Also in this strip mall was Snyder's Meats.  It was a butcher shop, and it sold top-quality meats.  But that wasn't all.  Snyder was the guy who started In-N-Out.  Why?  Because he was sick and tired of the crappy burgers his kids were getting at the various fast-food joints in the area.  Enough was enough, he finally said.
So he created In-N-Out.  His premise was simple:  quality beef, quality buns, quality fries, uncomplicated menu, fast service, and strictly drive-thru...and at a reasonable price.  He was right...and to this day, the In-N-Out offering hasn't changed that much, and they've held onto their affordability.
In-N-Out's burger meat is selected and ground to their specifications (aka Ol' Man Snyder's butcher specifications).  The same goes for the buns they use.  And their fries are real potato, not "manufactured."  What's more, Snyder saw the pitfalls of franchising.  Unless things have changed, every In-N-Out store was and still is company-owned.
But I've gone on long enough.  Stay in touch!
P.S.  Did you go to high school in La Puente or thereabouts?  I attended Edgewood, the politically dismissive step-sister to West Covina High.
P.P.S.  How about college?  Mt. SAC, perhaps?  Back in the day, SAC was called, "high school with ashtrays."