You may think that "spending all our time together" is basically the same as living together, but it is not. Not even close. If all else fails and you get into a disagreement, you can both retreat to your own homes, cool off, and then be fine. You don't have to deal with her fucking mess all over the bathroom, 10,000 hair products, makeup, long hairs all over the damn place, etc. she probably just has a cute overnight bag she brings over, and tidily packs it up and takes it home again when she leaves. She doesn't have to deal with your lazy ass leaving dirty dishes in the sink, or leaving your dirty underwear laying on the ground because you clean that shit up before she comes over. Once you are living together there's nowhere to run and hide, you have to learn how to deal with that shit, get over it, and move on. I lived with 2 women before my wife. One for 2 years, one for 3 years, and I never even bought a ring for either one of them. I dated my now wife for 1 year, we got engaged and lived together for another year, and now we've been married for a little over a year.
If you've been previously married, or been in several long term relationships where you lived with a woman, 6 months of living together may be all you need to make an educated decision on whether you want to spend the rest of your life with this woman or not. If you, or her, or god forbid both of you have never lived with someone you were in a relationship with, you need at least a year, preferably 2, to figure that shit out.
I don't care if it's not feasible because of her family, you're perfectly fine alienating them by eloping against their will, do the same damn thing and live together first. If you're going to piss them off when you get married, piss them off now and live together, what's the difference? The reason the divorce rate in this country is so high is because people are fucking dumb, and don't educate themselves with all the information available to themselves. Marrying a woman without living with her first is like buying a car without test driving it first. A lot of cars look great when you're staring at them in a controlled environment of a show room floor(dating, everyone is on their best behavior), but you really don't know anything until you take it for a test drive(live together).