First welcome to Sunline Owners Club! I moved your post to be it's own thread as it is a good topic on it's own rather then the 2011 thread you tagged onto. No worries, we help new members until they get the hang of the forum.
Now to the wires... The clearance lights, front, side and rear clearance lights are on the same daisy chain hookup. Meaning they go from light to light, connect the hot and the ground and then jump to the next one.
The good news is you at least have 2 working.... Now how to trouble shoot from here, there are a few ways, one using the hot side, the next the ground. You have to sort out what is not making the connection at the next light that is not working. The ground or the hot wire may be the problem, or both.
For the hot side method, If you have a volt meter or a 12 volt test light, power up the lights and start at the closest next non working light to what is working and probe for 12 volts. Use the meter or test light on a known good ground. If you have 12 volts, then the ground is bad. The unknown is, which light did they jump to next???
You will have to probe until you run out of lights to see if any have the 12 volt power at least. If you do have power, then try a temporary ground wire to that fixture and several may light up. Then you at least know which ones are still connected and have to figure out where the break in ground is.
That said, you can do this same test on the ground side. You need an ohm meter or a temporary ground wire long enough to probe around and start hunting at each fixture if there is a ground established.
By putting a temporary ground wire on one fixture may create the path for several others down the line to light up.
OR you have some how lost both the hot and ground and have to use the meter to tell where to start powering up the loop and back into where the break is.
Which ever method you do, this will be a hunt and peck mission. If you are lucky, it is only a ground wire that is lost on 1 light and all the others down stream will work once that ground is reconnected.
Hope this helps
PS, which 2 lights actually work? We may be able to help point to the next one in line.
Also, we have no wiring diagrams for your camper. They do however hook up like a standard trailer. This will get you close but on a trailer they use the frame as a ground wire and on the camper clearance lights, they run actual wires on both the hot and ground when jumping around the camper. Then that ground loop will eventually go to frame ground. Trailer Wiring Diagrams | etrailer.com