[Milo2001]

If you have worked on engines before, with a good manual, you should be able to accomplish all that you want. The cam bearing need to be done with the engine out of the car. With everything else you also want to do, at 260K miles you've got your money's worth out of it. If it were me, a new engine or new van would be ordered. Just doing the LIM gasket would probably buy you some more time. The gaskets i believe are about $300 complete, with a head rebuild of a coupl of hundred dollars. This would be a lot of work. You may want to consider just doing the LIM gasket and buy a case of oil for the leaking guides and just run the thing into the ground.

Good luck.