You might want to post in the Nevada state forum as most of the posters are from the LV area. You don't mention if you are driving or flying?
Even if you're driving your Jeep, this may be what you are looking for... Las Vegas Rock Crawlers
Just wanna take the tourist tour? Not really a 4x4 trip but... Red Rock Canyon Hummer Tours
Yet another tourist oriented outfit I've seen rolling though our town 60 miles west of LV on their way to Death Valley... Pink Jeep Tours
Titus Canyon is a very long day trip from Las Vegas. The time you are coming could be very hot and not so much fun out in the desert. The Spring Mountain National Recreation Area is just west of LV, and offers some interesting trails.
I live over the mountains in Pahrump, but we usually get out a couple times a week and might be available to guide you through some of the Spring Mountains. Drop me a PM if you are interested.
Here is a short video I made of a great Spring Mountain trip...