I am just about set with my set up. Here are a few pics of my trailer.
It has a 5200# axle on it, brakes, a custom made back gate> That I am having lettering made for. I have tried it out on one of my roofs shoots great. Pulls down the road wonderful. Even with both tanks full of water. Just got a few small things I am working on, But other than that, it's ready to go. I am going to do a roof for a family member this weekend.
I have a delavan 5850 pump 12 volt, that I got from my local farm supply company. They have been great to work with, if they don't have it, they will order it for me, and at prices similar to what I could get it for off the internet. I am using a BIG battery, 240 reserve minutes. A local company builds them. Had it out to practice on my roof when I finished it, Shoots farther than I wanted it to. I had to get some different nozzles. I went with the two 100 gallon PCO tanks more for the appearance than the need for that much capacity, But, I am glad I did. I did a roof last week for a friend, it was at a small building he owns, the roof was not real dirty, but great practice. There was no water around to rinse the grass down with. I filled up the second tank with water, and was all set. I built the ladder racks on the trailer, and installed a " deck" storage box on front to store all the small stuff. Right now, I have 5/8" hose from dayco. Not very expensive, I think these will be the second purchase after some money comes in, The first will be to purchase another pump. I went with brass nozzles and fittings. After reading alot on here, I decided to go that way instead of the stainless.
Looks like your getting there Dave, if you have the time get some of the Hercules bed liner for trucks and put down, incase you have chemical spill it will really help with the wood. I put it in my box truck and it has been a big saver, also if you can save up for it move to a air diaphram pump, I love the Yamada I started using a few weeks ago when my fatboy went out.