Don't bother getting the 1986 electrical/service manual, enough is available online for you to get by. Send me a private message and I can get you the appropriate links. You may also want to check eBay for manuals, as they do show up from time to time, but they seem to sell for too much (I would not pay more than $15-$20, as a new one is around $35).

Jerry Lemond or another more experienced source can say for certain whether the driveline will bolt in. It is my understanding that the frames differ between the two trucks in the area of the transmission crossmember, which is what the transmission mounts to. I have not been underneath an older Trooper to be able to say how different they might be.