Summer Memories by Audrey Beauchamp

Old cine film shot by Audrey Beauchamp, Rex's wife. Just beautiful. Loads of details and style for a period I, for one, don't often see. I think a lot of it is at the Astrodome.
Big thanks to Boastie for the link.
How many riders can you name? Can anyone fill in the gaps of where these tracks are? GI

GREAT UPDATE FROM ROGER! NEW UPDATE BELOW.

Here's my take to the best of my recollection about who the riders are and where in this 1973 footage:

I don't know the first half mile track, but here's who's coming back into the pits: 76 Frank Gillespie, 62 Corky Keener, 64 Gary Scott riding for the Triumph factory, 84x Eddie Wirth, 22 Terry Dorsch, 15 Mike Gerald, 88 Tom Rockwood, 80 Kenny Roberts
riding for Yamaha, and of course Rex Beauchamp is 31 on the factory H-D.
The first two indoor venues are the Houston Astrodome, the short track and then the TT. Add to the list 31z Rick Hocking, who along Mike Gerald rode the Astrodome races for Honda. 7 is Mert Lawwill, 9 is Gary Nixon, 4 is the great Bart Markel,
both multiple grand national champions. And I thought I saw #14, which would be Cal Rayborn. All legends.
Coming down the outdoor ramp is 69, TT specialist Sonny Burress, and future champ and present AMA dirt track director is 72 Mike Kidd.
The second Astrodome add 12 Eddie Mulder (you can't see his number, but it's his leathers). #6 is 1972 Grand National Champion Mark Brelsford, and I think this is the first or second year of year of the AMA assigning single-digit numbers only for
former GNC riders. (I also applaud Mike Kidd for recombining the gnc races back to a single combined grand national champion #1 rider again, apologies to Sammy Halbert for not getting to wear it while they were separated).
The outdoor half mile is the rescheduled Terre Haute, Indiana half mile which I was at. #11 is Don Castro riding for Yamaha, 13 Dave Aldana, (coming to Britain per your blog) may have been a factory Norton rider that year. 45 and16 are Canadian brothers Dave and Doug Sehl and 38 is Chuck Palmgren. A few years earlier, there were three Palmgren brothers racing with National numbers at the same time: Larry #5, Chuck, and Denny #16...pretty cool).
The last indoor is at some arena, and notably in the pits is #4 Markel (not the Triumph guy you see first, but right after in the red hat). The young blonde guy with the bare knee sure looks like a young Jay Springsteen, and in the Suzuki jacket is Gary Nixon, who rode for them at Daytona in 75 I think, so this film may not be all 1973.
A great piece of GNC history, thanks for sharing....roger.

From Will Stoner, 202F

I can add this: The indoor is the Michigan State fair Coliseum in Detroit. I’m almost sure I was there. I will try to figure out the novice numbers. I’m not convinced that’s Springer and I’m almost sure that’s not Nixon in the Suzuki jacket.
I’m pretty sure the cute girl is one of Dee (Dee’s Leathers) Johnson’s daughters, probably the one who is married to Randy Goss. Also, I don’t recall Springer ever having a big scar on his leg.
By copy, I will ask Dick Leonard number 70X, who was most surely there about who