Hi all, Mike again

Thanks for the responses so far.  I am indebted.  Now in true American
90's fashion, let me try to build more debt.
I looked at the bus.  Unfortunately after dark and it's parked where I
couldn't get too far under it without a lot of effort.  So I gave it a
general going over and talked to owner about an hour.
Owner in 20's.  Says dad bought new in '79 as 3rd family car and used
mostly just for camping until owner gets it to drive and has had it
since about '87.
Says 100K on engine but odometer broken.  
Back driver side has non-sliding window and back passenger doesn't
open in any way.  Owner claims these are original.
Bondo in two places on side from late middle eighties are both from
minor accidents.  Damage to front (dents) from drunk driver while bus
parked.  Rear driver side corner is all dented up.
Sliding door is not used and has tape etc. to help keep out air.
Apparently bus was roled in '89 completely over.  Wouldn't know it to
look at though.  Both cabin doors were replaced then and seem to fit
fine (except drivers side which has slightly bent wheel arch. this
doesn't jam door but leaves a little space for air to rush in.)
Hinge bent on pop top but top still pops fine.
Interior has dents/holes in sliding door panel and roof liner but
otherwise excellent.  Has all original curtains, screens etc.
Didn't drive it but he started it.  It was definately cold when he
started it.  It idled after a moment or so of him controlling it with
the pedal and idled fine afterward for about ten minutes.  Smoke at
first then cleared after couple minutes.  Revved up a few times and
let back down swiftly.. only a couple really small pin hole size back
fires.  Claims regular service and oil.
Oh yeah.. oil.  It leaks some.. he's not sure from where.  You could
see a little build up under engine but no puddle or spot where it's
been parked all winter. He disconected heaters completely because of
oil smell coming through.  Could smell oil burning when running but
didn't appear to be coming from exhaust. He says when he daily drove
it last summer he'd just top it occasionly .. guesses losing less than
a quart a week.
Driver front tire is worn out of balance with passenger.
Checked for rust under front floor pan.. in back of front wheel wells
and on around front axle at wheel and center connections.   Not any
rust at all really.  None in floor pans at all.  Engine compartment
also looked tight.

Questions.. given windows.. could this be a 79?
 How much trouble am I looking at for body work?
It seems to run good and he says well cruise fine on highway at 80 and
a little above even.
Said no major problem since new except the accidents and only didn't
start once.. was dead battery.

My thoughts.  Check more thoroughly for rust underneath and if
interested take to mechanic for compression and general look over
including the front end.

What do you guys think about the body work though..   Except for
sliding door not working.. you'd never know or even begin to guess it
was rolled.  He said something broken that hooks to roller for sliding
door too.  Door does work.. just takes finess to open and close it.
Camper top works but is really beat up..  is this hard to replace?

Thanks again
Mike