I echo Jack’s thoughts above. I would absolutely reach out to a Bennington dealer to check price and lead time, and whomever is going to do the replacement, their costs. Just figure out what your actual numbers are. Then circle back to the welding situation. Sounds very involved and beyond the norm from our original description, but then you at least know all the details.
At least within this forum, I don’t recall anyone doing a full replacement in recent years, so there may not be anyone with up to date accurate info currently. Based on that, perhaps you can report back and share once you find out current details. At least it helps establish a more up to date estimate these days.
And sorry to hear it falling separately from insurance. Ouch!!!