It's not *that* hard in a sense that you get a work momentum. But, that being said, little things like what I ran into (having to fly to visit a parent, etc) will ruin everything. Like a budget where you live paycheck to paycheck with no wiggle room, your time is spread thin. Any "surprise" obligations can ruin you.
I know that when I start taking more advanced courses, it simply won't be possible (IE when I transfer to UMD a year from now). I also don't get any time to party or attend many social functions. Which actually does impact me, as I do enjoy going out for drinks with coworkers.
But, if you want it, you'd make it work. It was -- work full time to pay the bills and pay for school, or don't go at all. It became obvious what the best choice was!
One does have to make sure there is time for themselves and not let anything bleed into that. Even if it's just 6 hours on a Sunday. Even if I have things that are due, that 6 hours is off limits. That's for me. You have to work very hard to keep centered, healthy, and focused.
I get easily frustrated with excessive work commitments too. That "one last thing" that my boss requests right before 4:30 means I'll have to run (literally) to class.
But I consider myself to be very employable now, and will only continue to be so. I'm in college with 2 years of analyst experience, 1 year of lab experience and a decent list of employer recommendations. Most of my friends graduating with their B.S have maybe a few REU's or internships. I have concrete ties with people in my area. When I get to the end of the schooling tunnel I'll have something to fall back on when the post-docs don't rain from the sky.
Also, I just really freakin' love physics. It's a hobby, and sure there are some problem sets that make me hate it. But only for a moment. Study what you love is a good mantra, especially when you only get 6-10 hours a week to yourself.
OP: I wouldn't suggest that it's easy to go school full time/work full time. But if you're only working 20 hours or so a week (30 depending on the work)-- it's entirely plausible to attend a standard school. You'll have more access to scholarships, staff support, peer support, and hands on learning than you would online. And I'm betting that doing a 2 year to 4 year school transfer would be cheaper than studying out of state, and online.
This may not have been the advice you wanted, but it is what it is.
Cheers