Dave is refering to the carbuerator, there's two ports on it, one is supply, the other is the return line if you run a primer bulb, when the carbuerator is primed it will just cycle the extra fuel back to the tank through the other line, but if you're not using a primer bulb, you need to cap off the other line, a short chunk of fuel line with a screw in the end works fine.

I don't know if home depot has the nylon line in bulk like Ace does (or at least mine does), check out the weedeater parts area, they sometimes have a package with a few feet of the stuff for a couple bucks... I think I ended up using around 3 feet for my plane... but check if they have bulk hose first. for the clunk line, check a hobby shop to see if they cary any tygon line, if that fails, try the mower shop, you'll only need a few inches, but don't even try to use the nylon for the clunk line, it's too stiff after sitting in fuel.

as for the choke, the stock choke on the ryobi's is a simple piece of sheet metal that pivots on one of the carb bolts and covers the carb opening, I've heard of some people cutting a super ball (bouncy ball from the quarter machines in the grocery store...) in half and gluing it to a toungue depresser and using that for a choke... on planes they don't really have to run on part choke to stay running if you stay on the throttle and run them up before take off, the prop puts enough load on them to warm them up quick enough... a choke doesn't have to be all that complicated...