Boa constrictor enclosure advice

[Joelb922]

So im picking up a gorgeous square tail boa pretty soon, and im gonna start building a home for him, now, ive built them before, but not one quite as advanced as i want to this go around, the general frame and body ive got down, i just dont know how im going to do the lighting, heat, and humidity. The enclosure is going to be 7'L x 3'H x 2'D.
Its gonna be a big tank, but i want it to look like i took a chunk out of a South American rainforest and threw it right into the enclosure, any advice on the 3 issues im having would be great, thank you.