Don't leave out the VW Bugs. Under the back seat, passenger side.
And the old vans' batteries were hard to get to, as was everything else back there.
As long as you kept the cover on the battery, the bug battery wasn't bad; and they lasted a long time, not being exposed to engine compartment heat.
The vans with the original doghouse-style motor - well, different story. Keeping the acid topped up on those was nearly impossible, if you didn't have the special factory auto-shutoff water bottle.