Gents,
I build a lot of scale helicopters in addition to planks.

Panel Lines:
Get your primer layer of paint to where you only need one more coat, say been sanded down to the 320 grit range. Get yourself some "ChartPak" tape at an art store, say 1/32 to 1/16" depending on your scale. Then use the tape to mark out every panel line on the primed surface. Then prime the whole thing again, with specific attention to putting more primer over the tape than over the rest of the model. Let dry, then remove the tape carefully. Lightly sand with 320-600 wet, only enough to get the surface roughed up and not enough to eat into the "panel lines." Access hatches can be made with card stock paper glued down before the tape, sorry forgot to mention that.

So, now you have a model ready to paint. You can do the rivets now or after the color, but before the clear coat.

Rivets:
Oh so many ways. Starwood Scale Models sells a kit for a very reasonable price for this, but it moslty consits of a syringe and needles with the point ground off and he has a special glue he uses. Lay out the rivet lines with very light pencil marks of a hard lead. Laser levels work really cool to line these up by the way. So once you have them laid out, you just go along with plain ole Elmers glue (white) or similar. Once you get the rhythm of laying them down it is fast and easy. You just get the flow going in the syringe and dot, dot, dot, dot, all along the marked line. Let the glue dry (it will be clear). No more sanding now or they are gone. Also by using the glue, if you goof, and I know you will because I do, you can just wipe it off with a damp rag and not leave any residue. These will be strong enough until you get the clear coat on. You can paint over them no problem. Personally, I prefer to do the rivets before the paint, I have friends that prefer to do the paint then the rivets, then the clear.

If you contact Starwood, please tell him I sent you. 1-650-851-9027, he is on the west coast.
Jack