The risk/reward plane seems very poorly slanted, compared to due-diligence. It also seems like custom mods could bring more sleepless nights than "belt-tension" might.
WRT changing an IM bearing in a vanagon, I'm not averse to making access panels if they can be nicely dressed. (I made one just for the master cylinder, since it is hidden behind the grille.) My Westy is at another location ATM, so I can't see where/if an opening could be made with any degree of elegance.