Hopefully you'll read this before you get there, because I see your reservation is later today.
I also had a "assigned at check-in time" situation with my room in summer 2016, and when I called the front desk while driving there (about 2 hours away), they told me there was no chance I would get a suite.
As a last shot, when I checked in on-property, I pretended I had never called, and calmly stated, "I'm a Seven Stars member, and I was wondering if you could do a suite upgrade for me."
The nice woman at the desk went to the back, came out a few minutes later, and said, "Yes, we were able to get a suite for you."
So I suggest you just ask when you show up if they can upgrade you to a suite (unless they already have you in one), and mention that you're a Diamond.
Sadly, the snow has been very bad in the Sierras this year, and Tahoe is reporting a very poor 19-inch base. They just recently opened the California side, which does make it easier for you, as you can use the Gondola which is walking distance from Harrah's.
I don't know... you may not want to bother. 19 inches is really crappy, and you'll probably be running into all kinds of rocks, sticks, and other obstacles.
Last year I went in mid-late January, and I had the opposite problem -- too much snow! It had just snowed heavily before I got there, and then there was like a 2-day break, one of which I used to drive there. I skied the next day and it was beautiful.
Then a cold, blizzard-like storm came in, and just dumped mounds of snow every day. The mountain was open in limited fashion on some days, but I didn't bother.
I was literally trapped in Tahoe for 10 days. The roads in and out were closed, and then only opened if you had both chains and snow tires (which I didn't). My car sat in the garage for over a week without budging. I ate most days within Harrah's, but sometimes walked to other places nearby for a change.
Finally it cleared up on my second-to-last day there, and I skied. It was not snowing and not windy, but it was COLD. Like 15 degrees the whole day. I was bundled up, but by the end of the day, I was shivering, and it took me awhile to warm up once back in the room. Never been that cold while skiing on a non-snowy, non-windy day.
I drove home the next day, but couldn't go down 395 because much of it was closed, so I had to go the long way through Sacramento. Then I forgot my skis, which I noticed when 30 miles away, so that added another 60 round trip. By the time I got home, I had driven 560 miles that day, a personal single-day record.
Highlander Bar does have a fairly good, CHEAP breakfast (and other late night food) after 11pm. Bartender is named Mike (I think) and is a very nice guy. The cook used to cut out 30 minutes early to get to another job, but I think that stopped after I complained about it, so it's probably really open til 6 now. You can play video poker up there, but keep in mind that you'll be bothered by lots of obnoxious drunks, especially on weeknights.
The restaurant in the basement (American Cafe) is surprisingly good and cheap. I believe they also have a Seven Stars discount. They do have crappy hours, and are closed after like 2pm on weekdays.