First off, Royal Purple is crap from the analysis I've seen.
If you want to read up on oil, and what is best, check out real life examples at
www.bobistheoilguy.com and look at the forums. Those guys really know their stuff and have oil analysis reports to back up what they tell you.
I have a friend who works in automotive oil testing. He says to go 1K miles for every quart the engine holds. So if the oil capacity is 5 qts, then 5K miles for oil changes. Don't bother with synthetic unless you're going to do extended oil change intervals of 10K miles or more.
I use Castrol GTX and have good oil analysis reports from it with a 5,000 mile interval.
If you want to use synthetic, Penzoil Platinum gets great results on 10,000 mile intervals in most cars. Again just review the oil analysis reports at the link above, or better yet have a couple performed on your Camaro to determine IT's best interval. I recommend Black Stone Labs.
Standard transmission fluid changes are every 30K miles.
As for the interior, use good cleaning/conditioning products like those from
www.griotsgarage.com and especially the leather cleaner/conditioner if you went that route. Also use a steam cleaner on the carpet once yearly.