The heat slowed me down but I'm plugging away. Last Sunday I got about half of the trench filled in and tamped down. That part was very nice clean brown dirt and I was able to bury the gas line directly in that. There is a lot of rock and gravel under the driveway and next to the shop - my buddy said I need 3-5" of sand around the pipe there to protect it. I got the sand in last night and started backfilling but it rained so I quit for the night.
Before the sand I also pressure tested the whole underground portion. It is unclear what the test pressure is, different locales have different codes, some say double operating pressure is required but for me that would be exactly one PSI. My buddy says they test mains at 100psi and my gauge only goes to 30. I did an hour at 15, then three days (so far) at 25 and it's been holding steady so I'm sure I'm good.
Hope to have the rest of it filled in and my driveway back to normal this weekend so I can get back to bigger and better things.
The wires in there are cat 5 cables for internet access in the shop. I normally would bury stuff like that in conduit but with how fast technology changes, I figured these will be abandoned sooner or later and conduit would be an unnecessary expense.