My old Mirada had 26 inch wheels. The frames are tanks...If the drops are horizontal I'd convert it to a 3 speed hub for cruiser action. You really can't climb worth a damn on the frames even with a triple. The stock cranksets were very cheap. I think these frames are the ideal candidate for single speed/rack grocery getter bikes. Any MTB quill stem will work from e-bay. They have the kalloy ones for about 20$ price including shipping. Get some goofy mustache bars and make a sweet single speed....

IMO gears don't make the bike move worth a damn. The frames are just tanks. If you insist on keeping it geared look at the cheapy Bulletproof cranks for 40$ they will give you a big gear and nice granny unit.