in accessible battery for jump starting.

[Jolly Roger bus 223]

a new member is on the way or very soon picking up a 2008 chevy cutaway with a dead battery.
the battery is under the bus and not accessible to jump start.
i have never had a vehicle with a battery like that?
i would think that the manufacturer would have installed remote lugs under the hood or close to the battery just for this situation?
i have never tried this because i have never had to deal with this situation BUT is it possible to go positive to alternator positive and engine block ground or to the start solenoid positive and engine block ground to jump start.
this member is in phone contact/text with me because i have a chevy bus and the manual for it for reference but mine is an 04 and my battery is under the hood.
has anyone ever tried these other options.
i mentioned them to the new member but also said talk to his mechanic where the bus is at.
there mechanic where the bus is at hasnt had time to get to there bus so they just want to get it started and check a few things out and or fix an evap code problem and hit the road to get it home.

[Kentucky Dreaming]

Jolly,
I know not much about buses. But some vans and trucks have remote studs for jump starting under the hood. Tell them to look for a stud near the underhood fuse block for positive and a stud or bracket near the power steering pump for negative. They may be well labelled or they may not.

[Vin1]

just realized i should update this, my bus he was talking about and it does have one under the hood
also has second one underneath unfortunately without a door to get to it

one battery had been replaced and the second one had not so it was drawing down the good battery
we got it lined out but in a few years when these need replacing will definitely go to agm or something long lasting so we hopefully rarely have to mess with them..

but the bus is running great once we got all that lined out
have to love the GM 6.0 motors!