I foresee horizontal boring in your future.
Plenty of it. ( Street and structure, perhaps much, much, more. )
I also expect that this run will entail an EE.
I've only ever had to run HV conduit in 'greenfield' conditions. So, I'm not too much help.
I do know that you don't want any collateral damage. That's always a bug bear for seasoned ground.
Back in the day, HV cables were rolled down quick and sloppy: no warning tapes, no warning strata. (sand as backfill, etc.)
You might be forced to pot-hole down with hydro-jets -- to sample worrysome ground.
When things get 'busy' you'll need to probe like crazy.
Documentation for old (buried) work is often pitiful.
You might take out a special insurance policy for this job.
