Sweet Fixie Brah

I just slapped together what could possibly be the most un-hip fixie in existence. I told my brother I'd make him one, but I'd been having some difficulty locating a vintage road bike. At our hunting lodge, I noticed a hunk of junk Huffy mountain bike, and to my surprise, it had horizontal dropouts. I didn't like the one piece crank, but I figured that I had nothing to lose, so I started putting her together. Mostly, I used stuff I already had laying around: track wheelset, 17 tooth cog, and some sweet handlebar grips. Unfortunately, I was a little short on chain, so I had to get a KMC Z410 Bicycle Chain
from Amazon, and I also had to get a Pyramid Track Cog Lockring. After acquiring the parts, everything fit together fairly nicely (all things considered). Fortunately, the inner chainring wasn't riveted, so I was left with the 40 and the fifty. Ideally, I would've disconnected those two, and just ran the 50, but they were riveted. Right now, I have it on the 50, and the chainline looks acceptable. If it gives me any problems, I'll run it from the 40 tooth, and probably go with a 14 tooth cog. The distance between the dropouts is a little longer than it should be, but the axles on the wheel are long enough, so I just need to crank on the bolts to bend the steel in a few centimeters on each side. I would also like to change the saddle, and chop a couple inches off each end of the handlebars. As of now, it's a functioning bike, but I don't think it has much of a long term future. There's a lot of rust, and the tightening bolts on the stem are completely rounded off, so I'll never be able to service the headset. The important thing is that my brother has his bike, and everything I put on there can be transferred over to a vintage road frame if I ever find one.