I was in the same position and overwhelmed with the features out there myself. It's too easy to get caught up in the, "well, I need XYZ feature," and I had to punch myself to get out of that mentality!!
Here is what I did:
1) Set up THE PRICE OF THE CAR + AND THE TOTAL OUT THE DOOR COST YOU WANT TO PAY. Dealerships will trap you with monthly payments. Ignore this number for the most part - but play around with online calculators so you're not shocked at how much you will have to pay monthly. Focus on the price of the car, and the price of the car only. For reference, a $23k car in California will have about $2500 worth of taxes and fees added on top. Means you are financing about $25k over x months.
2) Know your credit score and I recommend - if you are getting a loan - to do it through a credit union first. At the very least, you will know what rate you qualify for before the dealership pulls their bs.
3) Figure out what you value in a car. For me, #1 was reliability, #2 was MPG, #3 was utility, #4 was safety (I ended up with a small Honda SUV)
4) Ignore most fancy features. Most modern cars come with everything you will need - I will say a backup camera is a nice bonus, as are heated seats!!
Based on what you have said in your post, I would recommend a Toyota Rav4 (AWD), Honda CR-V, or Subaru Forester. It doesn't sound like you need a massive SUV, you really just need a hatch for the dog. If you can go a bit smaller there is the Subaru Crosstrek, Honda HR-V, etc. although I don't know about sleeping in them. But people definitely do it in the Forester, there is a whole thread on it in the Subaru Forester forum!