Its what the cost is for a welder and plasma cutter on the tool truck at my shop. Not overstated. I could get a less expensive one true.Well, it's pretty rough. Fixable, but unless you are emotionally attached, I agree with @rgranger , part it out and start fresh.
You are overstating welder cost, and scrap steel is not hard to come by for a fabricated steel version. However, your other damage is significant. It will suck up your free time for quite awhile doing some pretty messy jobs. Unless you really love fiberglass work, I'd call it done.
And time being money, that is a high cost to me and my girlfriend. We are both seriously busy and also I would like to spend some time with my daughter once and a while. Sigh. Its painful.
Parting out anything is a long term project, and one that I avoid in a business I know (automotive), that can easily suck space and time. I have the space to park a trailer. But putting the boat on jacks? Would rather strip the boat and dump it, then sell the trailer if I go that way. If we could recoup 3k total it would be what it cost us to buy initially. But I am well aware that is a year out minimum. Again time is money. Is it worth that when I would probably bill higher at my shop just working then I would make off parting it out. Hard call as I am a tight wad.