>Is it easy to tighten a rear view mirror to keep it from folding in on the
>highway?

Yes.
>Will it be
>evident what must be tightened when I remove it?

Yes again.

Remove the mirror from the van (two phillips head screws) and tighten the nut at the base of the mirror (its the only nut on the mirror).  Don't tighten the nut too much or the screw will pull out of the mirror.  If it comes apart or loosens up again quickly, Bus Depot has new mirrors for around $20.  I replaced the mirror and had to tighten the replacement, but it seems to hold ok now.

Bill