Sunlite has several different models and are available through quite a few distributors. There deluxe model has the bracket for disk brakes and for drum brakes as well. You'll probably need the threaded version for that bike but you will need to verify which one will fit.
I had a Western Flyer with that same frame. I ended up with a drum brake wheel on the front after adding the cantilever springer fork. You can mount a caliper brake to the lower part of the steer tube. You can also make a cross brace for your springer fork for mounting a brake.
You might also consider a shock fork- that's what I use. There aren't as many out there as there was a few years ago in 1 inch, but they are usually cheap bikes on craigslist- I got one new one on e-bay years back for about $60. Stay away from cheap AMF though. I thought I'd found a bike with a useable shock fork in the trash- an AMF mountain bike, but when I got it off I decided it wasn;t something I'd risk my neck on.