These small step ladders make that work on top of your tear a lot easier. I already had one of these and decided to buy another just like it since a regular six foot stepladder was so unwieldy. Just set one of these on each side of the trailer and you can go back and forth with your screwing, stapling, sealing, and painting without dragging a ladder from side to side. The top step is really stable and allows you to reach beyond half way on the top of a 5' wide trailer. They fold up to almost nothing for easy storage. You can easily reach up to 8' or so in height on one of these so they are quite handy for other chores around the house also. I've basically replaced my 6' stepladders with these. These are called Gorilla Ladders by Easy Reach and are very sturdy. I found these at Home Depot for about $30.
One of the smaller items that I found quite useful was a cheap stamping set from Harbor Freight. I've had these for many years and have used the heck out of them. They are really good for marking items left or right or numbering to keep track of custom pieces that have to be removed for painting and reinstalled.
One of the cheapest things you can use for organizing your work is a box of ziploc type snack or sandwich bags. Again, when you have to take all the hardware off your tear for painting, you can place them in these bags and mark them with a Sharpie to keep them organized for reinstalling. I also save the small cardboard mailing boxes to further organize the bags.
Hope you find this helpful.
Larry S.