My car has a lot more room in the engine compartment than a pan-based speedster. If I had a pan-based car (and I had two before this one), I'd absolutely put removable panels in the fenderwells and remove the wheels to gain access.
... but there's still the matter of reaching down through the tin to get to the plug itself. What I do with ANY plug I can't reach well is to employ a trick I learned back in the day at Bruner Brothers Mobil Service Station in the big town of Tremont.
Take an old straight spark-plug boot from a discarded set of wires, push the boot on the plug, and use the boot to spin the plug in the hole. You won't cross-thread it (as you can't get enough torque on it to do that) but you can get a plug started when you can't even touch the tip otherwise.
It works great.