That sounds workable, a little low on the budget but workable.
I need a bit more information on the sub. Do you know if it 4 ohm impedance or 8 ohm impedance? Is it a Dual Voice Coil? And what is the power handling on it? Kicker makes a lot of different subwoofers, and any info you can get on it will help determine which amplifier you might need to run.
Worst case if you don't have model numbers, pull the sub from the box and snap a picture of the magnet, and the cone. Usually the model number is on a decal on the magnet. And the cone will help determine the model as well. Take it from someone who has overpowered some subs, too many watts will melt voive colis and your subwoofer will seize up. It impresses friends, but it sucks to replace.
I looked at that same head unit. There are a couple of things to consider if you are going to use that type of head unit.
If you don't care for CDs, you're golden.
If you only want to run an amp for the suboofer, you can get the cheaper model (ida-x300) for 150 shipped from Crutchfield including your install gear and instructions. It will only allow you to hook up one amp for the subwoofer.
By the way, it will read Text info from the USB drives, it only shows track01 if you don't have ID tags on your MP3s that are compatible.
One of the strongest recommendations I make is run component speakers in the front doors. They cost a little more, but it makes a world of difference in how all your music sounds. Infinity has Reference series models that fit your Suburban, and traditional speakers that fit your rear doors. I found both sets for 180 total plus shipping.
If you're going to just run an amp on the sub and it doesn't need a ton of power, I can probably keep you under budget.
However you mentioned working on stuff away from the vehicle, so you might want to consider an amp for all of your speakers. Again, if the sub doesn't need a ton of watts, I can get an amp that will run the sub and all the speakers for you, but you'd be closer to 600 including a wiring kit.
Just out of curiosity, does that Suburban have the second battery mounting location under the hood?