i never had a van but did have an rv and i loved it untill the exusaust manafold blew a hole in it. and the good thing about the older cars/vans/rvs are that they are built to last and easy to fix.
You know, sometimes you can repair exhaust manifolds with furnace cement. this is the same stuff in exhaust repair kits (a sodium silicate base), but for 6 or 7 bucks you get 3 pounds of it or more.. also there's higher tensile strength furnace caulking for tougher fixes... use a brass fitting of some kind (bolt, screw, threaded valve) to close the manifold hole as much as possible.. ( tight enough to wedge securely, but not so much as to widen any cracks.. you'll see the brass deform on the iron, & as soon as you see that or crack spreading, stop.. & steel is too hard & will expand & contract for a stable fix..), then gloom the cement in there.. fiber reinforced furnace cement is best, but you can thoroughly knead about 10 or 15% fiberglass insulatio9n into it for about the same effect... plug & slather deeply & generously.. pay attention to manifold cracks..
also, exhaust gaskets can be repaired similarly, if you can get up where you need to push the material into the blowout..
fiberglass cloth can be used to make a bandaging cast if the cement is carefully diluted.. use acetate/polish remover to thin to about cake dough consistency, then use a couple heavier/thicker layers to finish & seal.. some of the cements can be cut with water.. use whatever the package says..
the best shit to use for fibers, though, if you can find it though, is asbestos pipe wrap.. mask & gloves at all times...
the main thing is to take care with the curing.. the fix is cheap, but it's slow.
you need a warm (65 degrees or better) area to let it set up for at least 18 hours on the first main layer, then at least 3 between each successive one.. preferably 6 for the second layer... THEN you have to cure it by idling for a couple hours & then drive gently...
you CAN superfrankenstien it over a shorter period, but i wouldn't do it on any large displacement engines...