DR Danise - It sounds like your New York trip is shaping up nicely. If I may, a word of advice from someone who's brought a few people to the Big Apple for their first trip there...
Yes, it's good to see as much of the island as you can. Theatre District. Chelsea. Greenwich Village. Lower East Side. Central Park. Chinatown. Etc., etc., etc. -Oh, and then there is Queens, Brooklyn, Harlem, etc., etc., etc. Oh, and the Cloisters too!
BUT... Just make sure you don't set yourself up for being tired and weary each day. Trust me on this one.
The on-and-off sight-seeing busses are a great deal - and if the weather is nice, an even better deal. But I'd highly suggest blocking off a good two or three or more hours to one attraction/location. This way you can relax and take your time exploring wherever you end up. *Actually, even if you just walk around Times Square, there are tons of things to do besides the theatres - quirky little shops, great little restaurants, great bakeries (especially over on 9th - I love Amy's Breads!), etc. *If you can track down a copy of last month's Gourmet magazine, they had a great basic guide to each of the major neighborhoods - even pointing out some of the lesser known monuments and memorials.
-I'm always amazed at how much walking I do when I get up in The City. Yes, I like walking, but there have been times when I've gotten back to my hotel room and wished I had some foot soak with me.
I guess my point is this: See as much as you want to see. Just make sure you don't end up tiring yourself out during the day, thus making your evening less enjoyable. -Or as I learned when I took one friend up to the city, don't do so much during the day that you end up falling asleep during the show you're seeing that night.

As for other discount codes, there's also Playbill.com and HitShowClub.com. Also, many of the show's own websites have specials available every now and then.
And as others have suggested, and I think I suggested the other day, if you're not in the mood for standing in line at TKTS, I'd take advantage of the discount vouchers. With them, you can purchase the tickets in advance, and you'll have more control over the location of your seats.
Oh, and as for Rush Seats, here's the link for the primer from Playbill.com. *Some of the Rush offers are for students only, some are for the general public.
http://www.playbill.com/celebritybuzz/article/82428.html