I did it,  and, I don't know if it would work or not,  but on the side vent
hoses, making them several times longer might be better.  Put them on the
tiny plastic hoses first...then the tank while it's leaned up on the front
brace just before lifting the back end up.  Also I'm curious myself, why
that crossover pipe isn't on the tank laying on top, rather than pulling it
down from the top of the cavity.  I reached through the frame from the front
wheel wells, put the gas filler back in and the vent on the right, but still
lack the left side... even though I made the small vent hose quite a bit
longer, I still cannot get my hands in there to slip it on the small plastic
vent tubing.  My rubber grommets were in great shape, I used a small amount
of grease to put the grommets back in.  Mine pulled out when I lowered the
tank.  I think I would take the filler tube and vent out first before
dropping the tank.  There is a big rubber grommet the filler tube punches
through. Pulling the filler spout first will make dropping the tank easier.
Pull the gas line off the right underside off the tank.. and let all the
gasoline drain out.
That's how I did it, and probably most of it was wrong or out of sequence..
as to an experienced person, I just did what worked...and I still wish I
would have put the vent hoses on the plastic lines first.  I had good access
to the top of the tank before I lifted it up.
Lyle Lathem
Vanagon GL
Quinlan, TX