Fred, you are right that a permanent panel is less work than a portable. The problem is that we always park the trailer in the deepest possible shade that we can find -- DW will reject a boondocking site that is too exposed, except in really cold weather. She grew up in the San Fernando Valley and thus has a deep-seated dislike of baking in the sun.
So that is why we absolutely have to have portable panels with the longest possible cable -- I have to search out a nearby patch of partial sunlight.
I will investigate the issue of voltage drop with clad aluminum cable to see if it acceptable. There is no way I can use ordinary copper ten gauge, unless it is very flexible. If I have to wrestle with balky cables, the "hassle factor" will kick in and we will use the portable panels less frequently. There is an old saying that "the best is the enemy of the good." Sometimes, second-best (like aluminum cable) is better than the gold standard of all-copper, because the gold standard might be more trouble than it's worth.
