I have something about you're "drive the speed limit" comment.
I went down to NYC this weekend as I often do, and in my Passat I got a mega 31.8 mpg using Premium gasoline in my 1.8 turbo 170 hp engine going a constant 85 miles per hour from Syracuse to NYC taking 81 south to highway 17. When I drive slower, say around 65 miles per hour I usually get about 31.9 or 32.0 mpg. The difference is so minute that it doesn't matter. (on my recent trip, the AC was on...I got sick of the radio being so high and hearing rice rockets farting)
Also with the change your oil every 3k miles comment...
In the Passat, I change it every 5,000 miles and it actually is a waste of money to change it every 3k miles. It's a long time debated discussion on when to change your oil, however many of my fellow VW Vortexers all follow (or most) the 5,000 mile oil change in our Passat.
Agreed, AC is a waste of gas when you don't need it.
The 4x4 capabilities in the Jeep is great, however don't expect it to be like a Wrangler. Casual off roading is more suitable (I.E.-getting to your fishing spot that you normally couldn't get to with your car and then some.)
Try and find a great Jeep owners website. I use one called VW Vortex at http://www.vwvortex.com
and use their forums to get advise on mods, fix it questions, etc. I am sure there is one for Jeeps.
Brooklyn, Queens, Manhattan, Staten, Uptown, what now? Lets make it happen.