New to attic growing....... input??

If your outside temps are great all year, do a polythylene greenhouse with tomatoes around the walls.

The Little Greenhouse - small pvc greenhouse kits

Only a little more than a couple of lights and no bills. Polythylene has excellent light transmission qualities, better than glass.

while an attic can be hard to control temp wise in your situation where it only gets to about 80 degrees would think its probably do able even without a/c, insulate your room well and dont skimp on your ventilation as you will need alot to keep the temp down

Use positive pressure, build a box for the plants (big box) seal it up, feed it air from the house below, make sure you have a 2:1 ratio of intake to exhaust, of course insulate it; all you need to worry about after that is radiant heat from the roof and siding.