Options for climbing Mont Blanc without gouter hut reservation

I got an invite to join a friend in Chamonix around late June through early July. The invite came in after the Gouter hut was sold out already. Tete Rousse still has some bivy spots available in late June.

Although I am more into alpine rock than peakbagging these days, I still do want to summit Mont Blanc sometime in my life, so I'm on the fence about whether to invest the time & money to go to Chamonix without the opportunity to stand on the cultural highpoint of Europe.

Myself & the friend both have basic glacier travel experience, mountain sense, climbed Rainier via standard routes, etc. We rock and ice climb but are looking for a walkup on Mont Blanc.

My limit for vert gain has been 7k'/day on Colorado 14ers, and I had no issue on summit day on Emmons (4600' gain). But that was after acclimating a lot; Chamonix is basically sea level. And the friend found summit day on DC to be very difficult (4k' gain). The point being: a summit day with >4k' gain would be very difficult for one or both of us.

As I understand, a hut reservation is required to climb mont blanc, so your options are the following:
1) Stay at Gouter hut (12.5k') -> 3k' summit day [sold out]
2) Stay at Tete Rousse hut (10.4k') -> 5k' summit day, and you're below the grand couloir rockfall zone [available ~6/25]
3) Italian route via Gonella Hut (10k') = 5500' summit day
4) 3 monts traverse via Cosmiques hut = 5k' gain but you're spending a lot more time at high elevation

Am I missing anything here?
- is it allowed/feasible to just randomly bivy somewhere else on the mountain?
- are there walkup reservations or other ways to get into the Gouter hut?
- if we stayed at tete rousse, we would climb the grand couloir in the early AM; but then it is not wise to descend the rockfall zone in the afternoon. Would we need to wait until the following night to descend?
- When does the climbing season end? Would ~6/25 be feasible for Gouter route, or is that too late
- Is there a walkup route that is usually done unroped, or do all routes require glacier travel? (yea I know there's always someone who would solo it, but I'm not looking to take unusual risks here.)

The summit of Mont Blanc is a big glacier, so there will be glacier travel no matter what.  The standard routes are like the standard route on Rainier: follow the great big trench and don't jump in a hole. I've personally seen the Trois Monts, Grand Mulets, and Gonella routes, and if I were you I'd go for the Trois Monts from Cosmiques and acclimate beforehand.  The Gonella route felt like quite a bit more work to me, and with a lot less traffic to beat in a path on the glacier.

I wouldn’t really think of any route on Mont Blanc as a “walkup” for what it’s worth. All the routes you mentioned are climbs of glaciers, so yes there is definitely significant glacier travel, crevasses, overhead hazard, and so on. Conditions are different every year. Last year local guides stopped guiding the Gouter in July because of rockfall for example, and new crevasses opened high up which caused route changes as well. But for strategies, apparently some people just blast it in a day from town, first lift up in the AM and up the Trois Mont and home for dinner! 

4) 3 monts traverse via Cosmiques hut = 5k' 4k' gain but you're spending a lot more time at high elevation

The Cosmiques Hut is 3,613 m (11,854 ft)

Mt Blanc is 4,807.81 m (15,774 ft)

One can camp in the Vallée Blanche. 

The route has some cracks but for the most part is a big walk in the sky. Earlier in the season the better. This year's snowpack is currently 50% of normal. Some will do an up and over going down Gouter.

Allen Sanderson wrote:

The Cosmiques Hut is 3,613 m (11,854 ft)

Mt Blanc is 4,807.81 m (15,774 ft)

3 monts traverse also loses and regains elevation between Cosmiques and Gouter hut. This adds up to 4,992' gain according to https://caltopo.com/m/4UETL. but, it's a good point that Cosmiques hut is higher and therefore better for acclimitization.

This year's snowpack is currently 50% of normal. Some will do an up and over going down Gouter.

Does this mean that late June is likely too late for Gouter or 3 monts?

Ellen S wrote:

Does this mean that late June is likely too late for Gouter or 3 monts?

At this point it means that one should have alternative plans. 

The slope below Maudit on Trois Monts can get a little steep/icy for an ax by July, but overall Trois Monts is pretty chill and went by far faster than expected. You could descend Gouter for less vert, but more logistics and possibly weight.

A lot of snow routes can be out by late June of a low snow year, but La Tour Ronde and Midi-du Plan make for great acclimatization routes if in.

In a normal snow year, solo glacier travel isn't unusual up there, but I wouldn't recommend it.

Camping next to Cosmiques is frowned upon/illegal, but common for a night or two. 

In general, I wouldn't plan on much moderate ice climbing by June of this year. At 5.8, there's some great routes on the Rouge side of the valley that would be considered 5-star most places but garner 2-3 star there. Arete de Papillions is good too (if busy) and the short 10- sections are easily aided; if not, I recall a single move finger jam with gear at your nose.