I did the same thing to my trailor. I added onto the sides, just butted up to the outside edge and welded it to it, in front of axles and behind. then made 1/4 inch diamond plate fenders, well gusseted so I could drive over them and even park on them to get my weight right at the tongue. It is a full 8 foot wide now, and tracks perfect behind a Duelly( I guess a bus is concidered a duelly too??)
A for wiring I got my stuff from Redneck Trailor Supply in Lincolnton NC. They have an online catalog you can download in Adobe I think.They will ship UPS for cost of shipping, next day if you order early enough. I got the 6 wire all in one, heavy duty cable. YOu will need one for trailor brakes, one for left signal, one for right signal, one for running or park lights, one for gound, this leaves one wire open you can use as a aux light for your trailor. They also have the connectors for trailor to truck. I got my brake actuator there too, it's a redline and no issues in 3 years from it. I drilled thru the cross members, but if I did it again, I would run conduit from front to rear for the cable. Use good connectors, and some no-ox gease on all connections. Also use multiple ground points to the frame.
Hope this helps. WOuld be happy to do it for you, but I don't think Bynum is very close to me
