apologies if this isn;t the right forum...

age and what seems to be massive geologic uplifting of the hills and mountains around here necessitate some smaller gearing. I'm a bit of a retro-grouch cause everything I own is at least 15 yrs old or more.
My 'go-to' machina is a std crankset (52-44) and Ultra 7 freewheel (13-21) 126 rearend.
I have too much stuff to change everything on this machine, I have too little DOSH to get another machina.
A 'varied' ride in my area will take me for miles of rolling terrain with small climbs and up 7-8 miles of continuous climbing in the 9% to 13% range and an equal amount of descending... (Santa Barbara County CA)
Which means I need a good gear mix in the high 70s to low 90s, and now also good mix in the low 60s to 40s.
A Compact Double - 50-34, seems the real solution. No desire to go triple. My current crank is Campy SR .
SO
*** My 1st 'Q' - what considerations should I give in putting a Compact crank to my older Ultra Freewheel based machine.***

No, I won't be spreadin the rear triangles, no new wheelz (meaning cassette), prolly stay with the 13-21 freewheel for now. BB shell is 68 Eng. Front and rear derailleurs are Shimano Indexed stuff of uncertain vintage.
I have a nice Campy BB (SR) that is just about broken-in.

*** Q2 - Are there Compact Cranks that will fit this square taper axle?***

Otherwise a good value Compact crank and maybe ISIS BB recommendation is appreciated.
I'm an olde pharte, but well seasoned in the art of sufferin, so the mid to low 40s is about the bottom I need to hit.
Thanks for any thoughts/comments/recommendations.