I see this is an old post. This will require special equipment as Prevost buses are 12' high. Prevost motor homes have a/c units and sat t.v. equipment on the roofs which make then 13' high. These sort of buses can be towed with a under lift, but only from the front. I would hope the engine fire did not damage any air lines, so the bus can build air for the suspension. You can not tow these buses from the rear, unless they are going to the scrap yard as the body will flex and bend. It may also cause some of the windows to pop out. This is from my experience working as a heavy truck and equipment mechanic for over 25 years. I worked at a shop for 5 years that serviced Prevost and MCI buses for 2 tour bus companies.
You could try some of the load boards, but that is a mixed bag. I have used Meadowlark in Billings, MT to move equipment for me. My contact there is Kim Starr, she is quick to get me a quote and then quick to dispatch the truck. They are not the cheapest, but they will get the job done. Freight Quote.com was ok, until they have been bought out by C.H. Robinson and their rates are expensive. These type of buses usually require a special trailer specifically for towing buses and nothing else, so the rates will probably be around $6 a mile +/-.