Hi
Just as with a car or truck, you may find that the damage is enough for the insurance guy to "total" the vehicle.
Repair wise, there are three basic alternatives:
1) Ignore the damage and move on (likely getting some sort of check from the insurance)
2) Pull the panels and replace them (yes it's a lot of work and cost)
3) Play with dent pullers to minimize the damage.
Insurance wise what's likely to happen:
1) You get a check for the total insured value of the trailer and hand it over to them.
--or--
2) You get a partial check for the trailer and keep it with a salvage title on it
Depending on your insurance policy and the company involved, the checks might be pretty substantial or a bit of a disappointment. Best to do a bit of research on what your trailer is likely worth. If they are a disappointment, you likely saved quite a bit of money on premiums over the last decade or so
There are a lot of threads here on the forum with owners in similar situations hashing out the "which option do I take". That is very much up to you. It's quite easy for the "rest of us" who have zero attachment to *your* trailer to suggest this or that. If it was *my* trailer, indeed there would be a bit of a tug on the heart involved.
Bob