Drum Brakes won't release

[Eotku]

I bought a 1970 chevy blazer a couple of months ago and today was the day I got it on the road. After driving it a few miles to work I noticed that the brake peddle was pretty much staying at the top of the stroke. When I started driving it home I could tell something was wrong. When I was in a parking lot and tried to backup I noticed that the truck wasn't wanting to roll. It felt like the parking brake was on but it wasn't. I only had a couple of miles to go and so took back streets to keep the speed low. The more I drove the hotter the brakes got. When I got home the front brakes were smoking hot. Rear were hot too but not smoking. I was only able to push the peddle down about 3/4 of an inch. When I first got the truck I did take all the drums off and looked at the brakes and they looked worn but OK. I did adjust them but wasn't sure how loose they should be. I adjusted them so the drums would just barely go on with hand pressure. So what are your thoughts? Master cylinder? Wheel cylinders? Adjusted too tight. I appreciate any insight you may have.