Like others said, learn more about your truck by taking it off road. You already have a lift, so figure out what you like, and what you don't like about it. You can go all out and break the bank, or you can do a more moderately priced suspension upgrade. Also, the big question for you to answer is...how much are you truly going to be exploring?
If you're going to explore trails in the mountains, I'd probably invest in more recovery gear. Do you have any of those? For example, a hi-lift jack, air compressor, shackles, towstraps, etc? From your profile pic, you have a nice rig. I'd just make sure you're prepared for the worst out there in the mountains prior to worrying too much about a suspension upgrade.
2010 Sandstorm TT--BajaRack Standard Basket Rack (Line-X)--BajaRack Ladder--Cobra 75 WX ST w/4' Firestik--U.S. Offroad Bumper--Warn Zeon Platinum 10-S Winch--2" Sirius Pro LED Lights--Springtail Solutions Side Basket--sPod HD--OEM Audio +--40" Sirius Pro LED Single Row Light Bar--Front Runner Rear Drawer--TRD Exhaust--Wet Okole Seat Covers--more to come...