So, it's been a LONG time since I last played with Cass as a companion, however her endslide made me wonder about something:

What exactly does Cass mean when she says "We were going full speed ahead... but facing backwards the whole time."? Is she saying the NCR was going full speed ahead but in the wrong direction or that The Courier and her were going full speed ahead but returning Pre-War technology to life the whole time?

I'm just baffled at the meaning of it.

Well, she is very pro-NCR, despite being also critical of them, so i took it meaning that she disagreed with you helping House to win.

I doubt it. If she did, she wouldn't help you. Plus it also mentions her heat skipping a beat at how House made Hoover Dam flow like it did before the War, something NCR couldn't get done.

"Just a little" Her dialogue makes it clear that she is a NCR patriot, and proud of it. And "facing backwards", giving control to remains of the old world instead of something that represents the new one?

Well, i suppose the endings were written in a way that lets everyone draw their own conclusions

It's a general statement that means the past will continue to influence us even though we are making progress.

Yeah, that's the gist of what I picked up from it. House is bringing progress rapidly and will if he wins, but NCR is slowly but surely working towards it in a vaguely Old World sense.