Those are all really good ideas. But since the truck is still mobile I think you would be better off to take it to a mechanic that can do any or all of those things but the 1st thing he should do is put an impact wrench on it and spin it right off.If that doesn't work he can go to plan B,C,or D. And he can even chase the threads with a die afterwards if needed.
It shouldn't cost anymore then the tools you might have to buy to attempt it yourself. And less chance of damaging the stud or bolt by torching or cutting it yourself. Cutting always has the possibility of an oops moment.
Good luck.
