Drilling holes in trailer roof to install solar: worth it?

agesilaus wrote:
Some folks are using super strong 3M tape and say it works as well as screws

That would depend on the type of roof, tape may hold on a solid fiberglass roof, but if you have a rubber roof membrane, you may find that your solar panels ripped off half your roof membrane when they were blown off after driving on the freeway. Even if the membrane is glued down that glue isn't meant to be structural.