No. That would be like assuming they have rooms for sale, so you should have no problems just showing up without a reservation and expecting to get a room. Maybe, maybe not. Your reservation guarantees it. Here, your payment guarantees it.

I received an offer to upgrade to a Studio King or Deluxe King for $50/nt. Is this the going rate? How much to move up to the Timberline?

I had checked out this thread ahead of my stay, and just checked in so thought I would update it.

I am a platinum and was recognized as such by the woman checking me in. I received an upgrade to a King with a fireplace (I don't know what the room category is). I checked in early (and had them note in my res I would be checking in early) and the woman at the desk told me the room they had me booked in was still occupied, but that she'd be happy to see if she could find me a different one. She did, and then apologized that the view wasn't going to be as good.
She also provided me with a bookmark of what the resort fee included, which also has your welcome cocktails ticket on the bottom. I was offered 500 points or a $10 food and beverage credit. In addition, I was also offered a small discount at the spa.
She was very friendly and efficient and I would say has a lot of experience with elites as before I could even ask the next question, she was explaining the what's and the whys. For example, as she was pointing out that the resort fee includes internet, she stated that of course, as a platinum I would already have internet, and then presented me with the spa discount. Very good service indeed.

Thanks for the update. Much appreciated.

Cheers.

As a Gold we received no special treatment whatsoever - in fact were assigned to a room next to the elevator (my pet peeve) and no upgrade (hotel was sold out). At some point I will provide a more detailed review in the master thread, but I would not expect anything special here. It is unfortunate that Marriott Resorts do not provide much in the way of elite benefits compared with other programs, esp. when there are no lounges.

If you were there during high season & the hotel was sold out, then upgrades are higher to come by due to folk paying for upgraded/better rooms.

Cheers.

Exactly. In fact I paid for one and this was what I got - one of the worst (upgraded) rooms in the hotel. Again, will address in the master thread.

After checking out, I wanted to update the rest of our stay.

I requested a late check out and was given until 1pm. As this is a resort, this was better than I was hoping for (I'm used to hearing a flat out no), and I was pleased. All of the staff we interacted with were friendly and helpful. I was particularly impressed by the valet staff who managed an amazing number of cars simultaneously in their limited driveway.

A couple of pluses and minuses:

*The resort fee - they charge the resort fee *by day* which I found very frustrating. I'm used to there being one resort fee per night, but we stayed only one night and were charged for two days of resort fee. I found this particularly frustrating as some of the stated benefits are not provided depending on when you check in or out. (For instance, they offer water and slippers which come in the late afternoon, after you would have already checked out).

*Ski valet - while this is very convenient, you must start from the hotel. As we rented elsewhere, and started right off on the slopes our first morning, when we went to send our skis back to the hotel and enjoy on-mountain apres-ski, it wasn't possible as our skis were missing the marriott sticker that gets them checked in at the hotel

*Vail bus - super convenient, picks up and drops off right outside the hotel, and there is a heated archway to stand in while waiting

*The walk back and forth from lionshead is easy, but not as close as some visitors have stated. The walk is along heated walkways so there is no ice, slush, etc on the way which does make it easier.

Overall we thought the hotel was nicer than a "standard" Marriott, and they certainly try to add thoughtful touches and extras to make it feel more like a true resort, but it is still not the Ritz or the Four Seasons(both of which are in Vail if that's more your speed

If staying only 1 night, would object to paying resort fee for two days, especially if you could not use ski valet.

Agree.