very late update... I ended up not attaching anything to the trailer since I was afraid the wind would tear away the fabric regardless of how much tape I used, and I would come back to a sanded trailer body
I did use the expensive grey '1 year no residue) from 3m to add tabs to my RV carpets for staking into the sand. It worked great for that.
This afternoon I was dismantling a homebuilt trailer of mine, and came across some white 'Duck' brand duct tape attached to an exterior wall. It was 3+ years old, has been outside every minute, from nearly-freezing to plus 120F and constant sun (las vegas weather). It peeled off with no complaints, and left no residue (on painted wood, paint
was Pettit Easy-poxy).
Just thought I'd leave another bit of info in case someone in the future is searching for 'duct tape' and is interested in some anectdotal long-term usage.