If you can find a good rust free fender, that's the easiest. Standardd going rate, as far as I can tell, runs about $100.00 or so. You might give Mike Dudek a call at iroll motors and see if he has a line on a good Amazon fender. If you need to splice and dice, I would think that flanging and carefully skip welding the new section in would be the way to go. Fiberglass replacement fenders are also available, or at least they were at one time. As far as a source, I'd guess a Google search is the answer. Be sure to undercoat your newly repaired fender properly, and especially periodically clean that area out with a hose and whatever tools it needs to keep the crud from accumulating back there. Edit: What side do you need, and how high up? Ive got some possible donor fenders, and if the panels aren't too big, they might be affordable to ship from 98362.