for the rock guards, glass and trailer skin....
-automotive soap/water first.
-follow this with undiluted vinegar (5% acetic acid)
use a soppin' wet cloth and go over the area several times lightly.
-next 90% isopropyl alcohol and again soppin' wet....
-now wash again lightly with soap/water and rinse throughly.
IF there is ANY residual deposits on the trailer skin
, use a 'automotive clay bar'
Detailing Clay Bar - Car Paint Cleaning | Detailing How-to Guide
now the clearcoat is as clean/bare as it's gonna get.
there may be some etching in the clearcoat from acid rain deposits or the mineral deposits
so now that it is REALLY REALLY CLEAN, apply your favorite automotive wax to protect the clearcoat.
IF the glass still has any residual deposits use a product like this...
Caswell Inc. - No Touch Products
which is basically a stronger acid glass cleaner.
following this cleaning,
i'd suggest a nice coat of rain-x or other window wax product...
and a coating of lexan/plastic polish for the rock guards....