Part it out. Valk parts are getting valuable.
Luckly, I've never had to deal with a hydro-lock repair, hope I never do. I'm sure you will get some responses on what it cost others to make the repairs. Having a dealer do it will be very $$$. Parting it out is one option, but that takes time and a lot of work.
Hopefully, someone close to you will come forward to buy it out right or help you repair it.
Wish you lived in my neck of the woods, I'd consider it.
Good luck.