Did a bolt shear, the tube seperate or did a bracket give way? Unless this was caused by corrosion to the cradle that might result in the replacement of the entire cradle from looking at my 4104 I really don't see anything that any farm welding shop should not be able to repair probably better than new. I have a small metal fab shop and this looks like something I would not hesitate to tackle but I am in Arkansas.
I would check the cradle channels (big channel pieces front and rear of the cradle ) and the braces and supports that connect the channels to see if anything twisted when the right rear of the cradle dropped. If the right side dropped and the left stayed up there is probably going to be some twisting of the supports connecting the channels. Looking at my 4104 I would bet if the right rear dropped the right hand inner brace would probably twist. Check the bolts or rivets that attach the braces and channels.
My advice would be to park the bus, get in a car and drive away from the interstate and from the vultures that hang out there into farm country and start looking for a welding shop with a mobile welder that can help you. (not that every shop along the interstates are blood suckers but I'll wager most are
Maybe stop at the local coffee shop in town and ask if anyone knows a farmer with a farm shop that can weld. In my country these guys are VERY experienced with fab work and welding and know how it is to be in a tough spot and need help.
This is all based on if part of the the cradle itself failed, if any part of the bus the cradle attaches to failed this will probably be bad news.
Does the bus have a tow hitch attached to the cradle?
Maybe someone will know of a shop.
Best of luck wish I was closer.