Chris: if it pops on deceleration, that is pretty common; also during warm-up; if it pops all the time it is likely the carbs are out of sync or that you are running a bit rich. You can pull the plugs and see if they are black or oily etc. to tell that. If aftermarket pipes or modified airbox is on your bike that can cause the popping, as can timing being slightly off, or an air leak in one of the carb boots, etc.
Top end noise is fairly common, but may indicate that your some of your valve clearances are too loose and need adjustment - a frustrating task because of the use of shims. Good news is that loose, which causes most of that noise, is much better than too tight, which can burn up valves. Also, the cam chain adjuster can be hanging up, not as likely on the new bikes as on my old ones. If the top end noise is bad at idle and goes away above 3K rpm it is likely that is the problem; if it is constant, then it is something else, likely valve clearances, which I would not worry about. But at 24,000 you are scheduled for a valve clearance check anyway.
If you don't have a shop manual, at least a Haynes, I'd suggest getting one if you are going to work on it yourself, of at least so you can know what you are going to try to tackle yourself and what you are going to pay the dealer some of your blood to do - and so the dealer won't be able to blow smoke at you telling you the problem is worse than it is.
Perhaps some of the guys who do all their own work, I don't anymore, will chime in here with some thoughts.
My last thought on the question might sound a bit strange, but you can't go by the appearance of the bike to tell hardly anything about mechanical maintenance. Some guys simply want their bikes to look like jewels and ignore the mechanical aspects until the bike blows up. Other bikes look like they have been "well ridden" but have been maintained mechanically very well. Often times if you don't know anything about how to maintain a bike, well, at least you know how to keep it looking nice, if you know what I mean.
Have someone who knows something about Triumph triples (preferably another owner who does some of his own wrenching) take a good look at it. I would if it were mine. 24K miles is THE major maintanence interval on these bikes, covering a lot more things than we are discussing here.
Good luck,
Monte