Getting back to your question about the belly skid. The issue here is that the wheelbase on the JKU is so long, it has a more difficult time clearing rocks and other obstacles than a shorter wheelbase jeep on the same sized tires. Consequently the under carriage will pay the price with extra abuse.
Based on the plan you wrote for how you plan to use the jeep, you shouldn't need to put skid plates on immediately. Until you do armor up the bottom you'll need to pay attention to the lack of protection and drive over obstacles with extra caution. Still, for long-term piece of mind I recommend investing in armor. Even if you only planned to drive logging roads there will be rocks, logs, etc. that will try to bite the bottom of your jeep.
As far as specific suggestions, I leave that to others on the forum. As with many jeep products, you can buy piece-by-piece or all at once. Designs run the spectrum from Gucci (aluminum) to more simplistic with matching prices. If the aftermarket changes as it did when jeep went from the TJ to the JK, in the next few years, JK parts will become more and more difficult to find as the manufacturers concentrate on the JL/JT market. With that in mind, I'd recommend trying to buy sooner, rather than later.
Thanks. About 20 years ago I switched from short wheelbase 4x4s to a 4x4 VW camper (that thing was a blast, btw) to double cab trucks (mostly to accommodate family) so I've gotten very used to dealing with a long wheelbase. The JKU feels like a nimble little cricket in comparison to my old F250!
I do plan to add some armor to the bottom - that evap box in particular looks very vulnerable. I just spent the afternoon yesterday re-routing some aux light wiring installed by the PO that was hanging inside the front fender well and under the frame to instead follow the stock loom down the pax side above the frame & gas tank for this same reason (I also added a 20 amp power feed to have aux power in the back). Boy, there is some close clearance between the pax side resonator and the rear bushing on the UCA - I would imagine that bushing needs to be replaced often if one spends a lot of at low speeds in hot weather...