The 707 was a wonderful bit of agricultural engineering. If something went wrong there was almost always a mechanical back up and a flight engineer.
Gear stuck up - open the panels in the flightdeck floor and wind it down. Gear doors stuck - back to in line with wing trailing edge, lift the panels and release the door locks. Down into Lower 41 for the nosegear.
Most bits of the pressurisation and aircon had a manual override.
Jammed stab - split the spoilers and fly it on the speed brake lever.
No hydraulics- electric back up for flaps.
Bleeds were definitely used for aircon and pressurisation. Qantas first 338C delivery flight from SEA to SYD was the first commercial aircraft non-stop US to Australia. Memory a bit rusty but I think they were running on one bleed and cabin altitude about 10,000 to save fuel.
I flew the DC8, much more forgiving in the flare than a 707. I was on the engineers panel for a couple of DC3 to DC8 conversions and was braced for the impact as they flared for a three pointer.
Use of inflight reverse for emergency descent was pretty scary, felt as though it was shaking itself to bits.
Much preferred the 707.
Boeing engineering definitely benefitted from the UK brain drain in the early 60s. I used to glide from Wenatchee, just up the road from Moses Lake, and quite a few of the Boeing gliding club were Brits.