Look up the towing capacity (and also the maximum tongue weight) of your Outback, then hit up a RV shop and see what they've got that meets the specs.
Pop-up campers are a pain in the dick as far as maintenance goes, you gotta close them up 100% dry or they can get moldy, and over time the canvas will tear and crack and will need to get patched/replaced/whatever. Friends of ours own one and they just replaced their canvas, after watching everything they went through with that we just decided to buy a box camper instead. But temperatures are higher and humidity probably isn't as big a deal down your way, so you'll probably be OK.
Ours came with a toilet and shower and stuff, but weirdly it was one of the cheapest box campers on the lot, the 'pod' campers and other ultralight stuff costs a lot more.
I looked at a few used campers before buying a new one, except nobody seems to know how to take care of their shit, and a camper that's left abandoned in someone's back yard for 4-5 years gets pretty fucking nasty, and figured getting a brand new one was a lot, uh, safer.