Okay, here's the scenario...went fishing on Saturday, put rods and reels in the boat and went to the pond. Noticed after getting there that back road dust was on everything. Didn't end up using the casting reel but I would like to make sure that the dust doesn't adversely effect an expensive reel so how would i clean it (as you can tell I'm new to owning a casting reel, it's a Lews Tournament Pro)?

it's probably fine. You'll know if it's not when using it. There's hundreds of videos on youtube on how to disassemble and clean reels. Get a casting reel cover for 5-6$ to avoid this from happening agian. 

Yup, cover is definitely in my future...for all reels spinning and casting. I just ordered something from Bass Pro not long ago and their deal of the day was reel covers for $2.99...I said no thanks but now i sure wished i had said yes...DOH!

Since you didn't use the reel and it's only exterior dust, I'd just rinse it off with tap water in the sink.  It'll be fine.

It's fine, wipe it off. 

Wipe it off, or run it under a gentle running water.

I would tell you to panic, but everyone beat me to a response and they were all nice about it.  

Check out those YouTube videos.  Your reel is very easy to keep wiped down and clean so make a habit of it.  Kind of like weapons maintenance to me.  You don't always need a full out clean and lube, but some TLC with a soft cloth and some q-tips (I like the foam ones) goes a long way. 

I'm not a big fan of the BPS reel covers.  I think they require much more effort to put on than the ones from Tackle Warehouse, so I find myself not using them. Sort of defeats the purpose.  The TW ones are more of a clamshell fit with a Velcro strap to secure it.  I'm sure there are similar offerings by other companies.  I can't stress the importance of rod covers enough either but that's for a different post.