I'm not a painter/bodyguy but I have done a fair amount of it over the years here and there.
Not so long ago I painted my kr660 (b I think). It was way more work than I expected.
Granted I've never done any paint estimating so don't have any experience to speak of there. But I discovered a drawer has a lot of surface area.
The 660 is basically your box with a drawer bank attached, so with your top box and side boxes you will have quite a bit more to do surface area wise.
The shop I was working in was/is a mechanical shop belonging to a friend of mine. Things were slow so I had basically the equivalent of 2, 2 1/2 bays to work in which was a good thing as it took way more space than I thought it would also.
I had a bit more bodywork to do than it appears you do. At some point in the past my box looks like it was backed into on one side. These boxes are double walled beasts though and it didn't hurt the inner structure at all. I was able to straighten the one side and hammer a piece of box channel down the area under the aluminum vertical trim piece, A few spot welds, some drawer straightening - not a lot, like 3 drawers had face dings from the same incident, and its as strong as ever, possibly more so.
Those aluminum trim strips don't seem to be readily available btw. The vertical side ones come off pretty easy, just a few rivits. I was able to mostly straighten out my dented one and switched its location when I put it back on, and also switched up the drawers (which I didn't fill so still showed a little) looking at the box you would never know it was hit. Unless you were a bodyman and looking way harder at my box than anybody is likely to.
The aluminum trim strips on the drawers are on there with a seriousness. There are posts around about how to take them off and reattach them, but after some careful attempts to do so I decided to tape them off instead.
That took awhile, but not too bad. Less time than removing them, making a tool and reattaching them, which may or may not be as good as factory. They are on there pretty good.
Mainly I was worried about destroying one since they don't seem to be available either, or making them look worse. Plus time was getting to be a factor.
I was planning on painting everything but the inside of the box was actually in really good shape, and the outside of the inner portions of the drawers were also like new except for a half dozen areas. The guy I get my painting supplies from was able to match snap on red dead on. Not his first time, lol. So I was able to save some time and money in those areas.
Oh, before I forget, when I was power washing the box I noticed it didn't drain very well at all. Probably a good thing overall, but one never knows what will happen, so I drilled 4 small holes in the bottom of the box. I believe they are in the heavy box channel where the wheels bolt on, but its been awhile. So no direct holes into the interior, but if something gets spilled or if it should get rained on it will eventually drain.
When I got the box for $500 I figured I could fix the dent and paint it in a couple three days of moderate work, and maybe spend a $100 or so.
Ended up being a full week of more than moderate labor, and I quit counting when I passed $200 in materials. I'm pretty sure you will be faster than I am, and can probably wiggle the sandpaper, primer and what not. Maybe the paint also. Mine is SS btw, BC is going to be even more effort.
I spent $500, plus prolly $250, for a total of $750 and a week of labor for a box that's work around $1,200 to $1500ish. Oh, and drawer liner, like $50 for that I think. White lithium spray also, half dozen cans of that. Didn't come out ahead financially. I could have rustled up a headgasket job, made up the difference in a day and a half of actual moderate labor and bought a $1500 box already looking new.
Or, just used the box as it was, it was fine functionally.
My long winded way of saying, another vote for use it like it is.
If you do paint it, I'd stick with the red and maybe save yourself some time/effort and money.
Then again if you want to strip it all down to bare metal and go crazy just so you can have the satisfaction of having done it, then paint it whatever color you want. No one is going to have a real appreciation of the effort unless they have painted one themselves though.
Edit: I also have basically the same top box you do, its roughish looking and covered with stickers from my younger days. I was originally planning on painting it also, would have to force me to at gun point now though.
